diff --git a/theatre/shared/src/utils/addresses.ts b/theatre/shared/src/utils/addresses.ts
index 17827c2..a4040ae 100644
--- a/theatre/shared/src/utils/addresses.ts
+++ b/theatre/shared/src/utils/addresses.ts
@@ -1,12 +1,23 @@
-import type {
-  $IntentionalAny,
-  SerializableMap,
-  SerializableValue,
-} from '@theatre/shared/utils/types'
 import type {ObjectAddressKey, ProjectId, SheetId, SheetInstanceId} from './ids'
 import memoizeFn from './memoizeFn'
 import type {Nominal} from './Nominal'
 
+/**
+ * Addresses are used to identify projects, sheets, objects, and other things.
+ *
+ * For example, a project's address looks like `{projectId: 'my-project'}`, and a sheet's
+ * address looks like `{projectId: 'my-project', sheetId: 'my-sheet'}`.
+ *
+ * As you see, a Sheet's address is a superset of a Project's address. This is so that we can
+ * use the same address type for both. All addresses follow the same rule. An object's address
+ * extends its sheet's address, which extends its project's address.
+ *
+ * For example, generating an object's address from a sheet's address is as simple as `{...sheetAddress, objectId: 'my-object'}`.
+ *
+ * Also, if you need the projectAddress of an object, you can just re-use the object's address:
+ * `aFunctionThatRequiresProjectAddress(objectAddress)`.
+ */
+
 /**
  * Represents the address to a project
  */
@@ -23,6 +34,8 @@ export interface ProjectAddress {
  * sheet.address.sheetId === 'a sheet'
  * sheet.address.sheetInstanceId === 'sheetInstanceId'
  * ```
+ *
+ * See {@link WithoutSheetInstance} for a type that doesn't include the sheet instance id.
  */
 export interface SheetAddress extends ProjectAddress {
   sheetId: SheetId
@@ -31,7 +44,9 @@ export interface SheetAddress extends ProjectAddress {
 
 /**
  * Removes `sheetInstanceId` from an address, making it refer to
- * all instances of a certain `sheetId`
+ * all instances of a certain `sheetId`.
+ *
+ * See {@link SheetAddress} for a type that includes the sheet instance id.
  */
 export type WithoutSheetInstance<T extends SheetAddress> = Omit<
   T,
@@ -42,7 +57,10 @@ export type SheetInstanceOptional<T extends SheetAddress> =
   WithoutSheetInstance<T> & {sheetInstanceId?: SheetInstanceId | undefined}
 
 /**
- * Represents the address to a Sheet's Object
+ * Represents the address to a Sheet's Object.
+ *
+ * It includes the sheetInstance, so it's specific to a single instance of a sheet. If you
+ * would like an address that doesn't include the sheetInstance, use `WithoutSheetInstance<SheetObjectAddress>`.
  */
 export interface SheetObjectAddress extends SheetAddress {
   /**
@@ -57,15 +75,32 @@ export interface SheetObjectAddress extends SheetAddress {
   objectKey: ObjectAddressKey
 }
 
+/**
+ * This is a simple array representing the path to a prop, without specifying the object.
+ */
 export type PathToProp = Array<string | number>
 
+/**
+ * Just like {@link PathToProp}, but encoded as a string. Since this type is nominal,
+ * it can only be generated using {@link encodePathToProp}.
+ */
 export type PathToProp_Encoded = Nominal<'PathToProp_Encoded'>
 
+/**
+ * Encodes a {@link PathToProp} as a string, and caches the result, so as long
+ * as the input is the same, the output won't have to be re-generated.
+ */
 export const encodePathToProp = memoizeFn(
   (p: PathToProp): PathToProp_Encoded =>
+    // we're using JSON.stringify here, but we could use a faster alternative.
+    // If you happen to do that, first make sure no `PathToProp_Encoded` is ever
+    // used in the store, otherwise you'll have to write a migration.
     JSON.stringify(p) as PathToProp_Encoded,
 )
 
+/**
+ * The decoder of {@link encodePathToProp}.
+ */
 export const decodePathToProp = (s: PathToProp_Encoded): PathToProp =>
   JSON.parse(s)
 
@@ -76,52 +111,35 @@ export interface PropAddress extends SheetObjectAddress {
   pathToProp: PathToProp
 }
 
+/**
+ * Represents the address of a certain sequence of a sheet.
+ *
+ * Since currently sheets are single-sequence only, `sequenceName` is always `'default'` for now.
+ */
 export interface SequenceAddress extends SheetAddress {
   sequenceName: string
 }
 
-export const getValueByPropPath = (
-  pathToProp: PathToProp,
-  rootVal: SerializableMap,
-): undefined | SerializableValue => {
-  const p = [...pathToProp]
-  let cur: $IntentionalAny = rootVal
-
-  while (p.length !== 0) {
-    const key = p.shift()!
-
-    if (cur !== null && typeof cur === 'object') {
-      if (Array.isArray(cur)) {
-        if (typeof key === 'number') {
-          cur = cur[key]
-        } else {
-          return undefined
-        }
-      } else {
-        if (typeof key === 'string') {
-          cur = cur[key]
-        } else {
-          return undefined
-        }
-      }
-    } else {
-      return undefined
-    }
-  }
-
-  return cur
-}
-
-export function doesPathStartWith(
-  path: (string | number)[],
-  pathPrefix: (string | number)[],
-) {
+/**
+ * Returns true if `path` starts with `pathPrefix`.
+ *
+ * Example:
+ * ```ts
+ * const prefix: PathToProp = ['a', 'b']
+ * console.log(doesPathStartWith(['a', 'b', 'c'], prefix)) // true
+ * console.log(doesPathStartWith(['x', 'b', 'c'], prefix)) // false
+ * ```
+ */
+export function doesPathStartWith(path: PathToProp, pathPrefix: PathToProp) {
   return pathPrefix.every((pathPart, i) => pathPart === path[i])
 }
 
+/**
+ * Returns true if pathToPropA and pathToPropB are equal.
+ */
 export function arePathsEqual(
-  pathToPropA: (string | number)[],
-  pathToPropB: (string | number)[],
+  pathToPropA: PathToProp,
+  pathToPropB: PathToProp,
 ) {
   if (pathToPropA.length !== pathToPropB.length) return false
   for (let i = 0; i < pathToPropA.length; i++) {
@@ -131,7 +149,9 @@ export function arePathsEqual(
 }
 
 /**
- * e.g.
+ * Given an array of `PathToProp`s, returns the longest common prefix.
+ *
+ * Example
  * ```
  * commonRootOfPathsToProps([
  *   ['a','b','c','d','e'],
@@ -140,8 +160,8 @@ export function arePathsEqual(
  *  ]) // = ['a','b']
  * ```
  */
-export function commonRootOfPathsToProps(pathsToProps: (string | number)[][]) {
-  const commonPathToProp: (string | number)[] = []
+export function commonRootOfPathsToProps(pathsToProps: PathToProp[]) {
+  const commonPathToProp: PathToProp = []
   while (true) {
     const i = commonPathToProp.length
     let candidatePathPart = pathsToProps[0]?.[i]
diff --git a/theatre/shared/src/utils/createWeakCache.ts b/theatre/shared/src/utils/createWeakCache.ts
deleted file mode 100644
index a12398c..0000000
--- a/theatre/shared/src/utils/createWeakCache.ts
+++ /dev/null
@@ -1,24 +0,0 @@
-export default function createWeakCache(): WeakCache {
-  const cache = new Map()
-  const cleanup = new FinalizationRegistry((key) => {
-    const ref = cache.get(key)
-    if (ref && !ref.deref()) cache.delete(key)
-  })
-
-  return function getOrSet<T extends {}>(key: string, producer: () => T): T {
-    const ref = cache.get(key)
-    if (ref) {
-      const cached = ref.deref()
-      if (cached !== undefined) return cached
-    }
-
-    const fresh = producer()
-    cache.set(key, new WeakRef(fresh))
-    cleanup.register(fresh, key)
-    return fresh
-  }
-}
-
-export interface WeakCache {
-  <T extends {}>(key: string, producer: () => T): T
-}
diff --git a/theatre/shared/src/utils/deepMerge.ts b/theatre/shared/src/utils/deepMerge.ts
deleted file mode 100644
index 15f7a97..0000000
--- a/theatre/shared/src/utils/deepMerge.ts
+++ /dev/null
@@ -1,20 +0,0 @@
-import type {DeepPartialOfSerializableValue, SerializableMap} from './types'
-
-export default function deepMerge<T extends SerializableMap>(
-  base: T,
-  override: DeepPartialOfSerializableValue<T>,
-): T {
-  const merged = {...base}
-  for (const key of Object.keys(override)) {
-    const valueInOverride = override[key]
-    const valueInBase = base[key]
-
-    // @ts-ignore @todo
-    merged[key] =
-      typeof valueInOverride === 'object' && typeof valueInBase === 'object'
-        ? deepMerge(valueInBase, valueInOverride)
-        : valueInOverride
-  }
-
-  return merged
-}
diff --git a/theatre/shared/src/utils/deepMergeWithCache.ts b/theatre/shared/src/utils/deepMergeWithCache.ts
index 601fcc7..a859ecf 100644
--- a/theatre/shared/src/utils/deepMergeWithCache.ts
+++ b/theatre/shared/src/utils/deepMergeWithCache.ts
@@ -39,7 +39,7 @@ import type {DeepPartialOfSerializableValue, SerializableMap} from './types'
  *
  * 4. Both `base` and `override` must be plain JSON values and *NO* arrays, so: `boolean, string, number, undefined, {}`
  *
- * Rationale: This is used in {@link SheetObject.getValues()} to deep-merge static and sequenced
+ * Rationale: This is used in {@link SheetObject.getValues} to deep-merge static and sequenced
  * and other types of overrides. If we were to do a deep-merge without a cache, we'd be creating and discarding
  * several JS objects on each frame for every Theatre object, and that would pressure the GC.
  * Plus, keeping the values referentially stable helps lib authors optimize how they patch these values
diff --git a/theatre/shared/src/utils/defer.ts b/theatre/shared/src/utils/defer.ts
index 983ecf4..8abf22f 100644
--- a/theatre/shared/src/utils/defer.ts
+++ b/theatre/shared/src/utils/defer.ts
@@ -5,6 +5,28 @@ export interface Deferred<PromiseType> {
   status: 'pending' | 'resolved' | 'rejected'
 }
 
+/**
+ * A simple imperative API for resolving/rejecting a promise.
+ *
+ * Example:
+ * ```ts
+ * function doSomethingAsync() {
+ *  const deferred = defer()
+ *
+ *  setTimeout(() => {
+ *    if (Math.random() > 0.5) {
+ *      deferred.resolve('success')
+ *    } else {
+ *      deferred.reject('Something went wrong')
+ *    }
+ *  }, 1000)
+ *
+ *  // we're just returning the promise, so that the caller cannot resolve/reject it
+ *  return deferred.promise
+ * }
+ *
+ * ```
+ */
 export function defer<PromiseType>(): Deferred<PromiseType> {
   let resolve: (d: PromiseType) => void
   let reject: (d: unknown) => void
diff --git a/theatre/shared/src/utils/didYouMean.ts b/theatre/shared/src/utils/didYouMean.ts
index 146d03b..92e47be 100644
--- a/theatre/shared/src/utils/didYouMean.ts
+++ b/theatre/shared/src/utils/didYouMean.ts
@@ -1,5 +1,13 @@
 import propose from 'propose'
 
+/**
+ * Proposes a suggestion to fix a typo in `str`, using the options provided in `dictionary`.
+ *
+ * Example:
+ * ```ts
+ * didYouMean('helo', ['hello', 'world']) // 'Did you mean "hello"?'
+ * ```
+ */
 export default function didYouMean(
   str: string,
   dictionary: string[],
diff --git a/theatre/shared/src/utils/ellipsify.ts b/theatre/shared/src/utils/ellipsify.ts
index cbaf36d..4949481 100644
--- a/theatre/shared/src/utils/ellipsify.ts
+++ b/theatre/shared/src/utils/ellipsify.ts
@@ -1,3 +1,11 @@
+/**
+ * Truncates a string to a given length, adding an ellipsis if it was truncated.
+ * Example:
+ * ```ts
+ * ellipsify('hello world', 5) // 'hello...'
+ * ellipsify('hello world', 100) // 'hello world'
+ * ```
+ */
 export default function ellipsify(str: string, maxLength: number) {
   if (str.length <= maxLength) return str
   return str.substr(0, maxLength - 3) + '...'
diff --git a/theatre/shared/src/utils/errors.ts b/theatre/shared/src/utils/errors.ts
index f265fa8..00b6f99 100644
--- a/theatre/shared/src/utils/errors.ts
+++ b/theatre/shared/src/utils/errors.ts
@@ -1,3 +1,10 @@
+/**
+ * All errors thrown to end-users should be an instance of this class.
+ */
 export class TheatreError extends Error {}
 
+/**
+ * If an end-user provided an invalid argument to a public API, the error thrown
+ * should be an instance of this class.
+ */
 export class InvalidArgumentError extends TheatreError {}
diff --git a/theatre/shared/src/utils/forEachDeep.ts b/theatre/shared/src/utils/forEachDeep.ts
index be188d1..53f2952 100644
--- a/theatre/shared/src/utils/forEachDeep.ts
+++ b/theatre/shared/src/utils/forEachDeep.ts
@@ -1,6 +1,29 @@
 import type {PathToProp} from './addresses'
 import type {$IntentionalAny, SerializableMap} from './types'
 
+/**
+ * Iterates recursively over all props of an object (which should be a {@link SerializableMap}) and runs `fn`
+ * on each prop that has a primitive value (string/number/boolean) and is _NOT_ null/undefined.
+ *
+ * Example:
+ * ```ts
+ * forEachDeep(
+ *   // The object to iterate over. The `fn` is going to be called on `b` and `c`.
+ *   {a: {b: 1, c: 2, d: null, e: undefined}},
+ *   // the function to run on each prop
+ *   (value, pathToValue) => {
+ *     console.log(value, pathToValue)
+ *   },
+ * // We can optionally pass a path prefix to prepend to the path of each prop
+ * ['foo', 'bar'])
+ *
+ * // The above will log:
+ * // 1 ['foo', 'bar', 'a', 'b']
+ * // 2 ['foo', 'bar', 'a', 'c']
+ * // Note that null and undefined values are skipped.
+ * // Also note that `a` is also skippped, because it's not a primitive value.
+ * ```
+ */
 export default function forEachDeep<
   Primitive extends string | number | boolean,
 >(
diff --git a/theatre/shared/src/utils/getDeep.ts b/theatre/shared/src/utils/getDeep.ts
index 14aba08..5c7261d 100644
--- a/theatre/shared/src/utils/getDeep.ts
+++ b/theatre/shared/src/utils/getDeep.ts
@@ -2,6 +2,18 @@ import lodashGet from 'lodash-es/get'
 import type {PathToProp} from './addresses'
 import type {SerializableValue} from './types'
 
+/**
+ * Returns the value at `path` of `v`.
+ *
+ * Example:
+ * ```ts
+ * getDeep({a: {b: 1}}, ['a', 'b']) // 1
+ * getDeep({a: {b: 1}}, ['a', 'c']) // undefined
+ * getDeep({a: {b: 1}}, []) // {a: {b: 1}}
+ * getDeep('hello', []) // 'hello''
+ * getDeep('hello', ['a']) // undefined
+ * ```
+ */
 export default function getDeep(
   v: SerializableValue,
   path: PathToProp,
diff --git a/theatre/shared/src/utils/getPropsInCommon.tsx b/theatre/shared/src/utils/getPropsInCommon.tsx
deleted file mode 100644
index 65282a4..0000000
--- a/theatre/shared/src/utils/getPropsInCommon.tsx
+++ /dev/null
@@ -1,16 +0,0 @@
-import type {$FixMe} from './types'
-
-const getPropsInCommon = (a: $FixMe, b: $FixMe): (string | number)[] => {
-  const keysInA = Object.keys(a)
-
-  const inCommon: (string | number)[] = []
-  for (const key of keysInA) {
-    if (b.hasOwnProperty(key)) {
-      inCommon.push(key)
-    }
-  }
-
-  return inCommon
-}
-
-export default getPropsInCommon
diff --git a/theatre/shared/src/utils/identity.ts b/theatre/shared/src/utils/identity.ts
deleted file mode 100644
index 136e85c..0000000
--- a/theatre/shared/src/utils/identity.ts
+++ /dev/null
@@ -1,3 +0,0 @@
-export default function identity<T>(a: T) {
-  return a
-}
diff --git a/theatre/shared/src/utils/index.ts b/theatre/shared/src/utils/index.ts
index c6ca1a9..7993c1d 100644
--- a/theatre/shared/src/utils/index.ts
+++ b/theatre/shared/src/utils/index.ts
@@ -1,6 +1,11 @@
-import type {VoidFn} from './types'
-
-export const voidFn: VoidFn = () => {}
-
+/**
+ * This is just an empty object used in place of `{}` when you want to:
+ * 1. Not create many new objects (less GC pressure)
+ * 2. Have the empty object be a singleton (so that `===` works), so it can be fed to memoized functions.
+ */
 export const emptyObject = {}
+
+/**
+ * The array equivalent of {@link emptyObject}.
+ */
 export const emptyArray: ReadonlyArray<unknown> = []
diff --git a/theatre/shared/src/utils/memoizeFn.ts b/theatre/shared/src/utils/memoizeFn.ts
index 70fe471..e7f9f15 100644
--- a/theatre/shared/src/utils/memoizeFn.ts
+++ b/theatre/shared/src/utils/memoizeFn.ts
@@ -1,5 +1,7 @@
 /**
- * Memoizes a unary function using a simple weakmap.
+ * Memoizes a unary function using a simple weakmap. The argument to the unary
+ * function must be WeakCache-able, which means it must be an object and not a plain
+ * number/string/boolean/etc.
  *
  * @example
  * ```ts
diff --git a/theatre/shared/src/utils/minimalOverride.ts b/theatre/shared/src/utils/minimalOverride.ts
index 2df3480..7d192b2 100644
--- a/theatre/shared/src/utils/minimalOverride.ts
+++ b/theatre/shared/src/utils/minimalOverride.ts
@@ -21,10 +21,6 @@ function typeOfValue(v: unknown): ValueType {
   }
 }
 
-/**
- * @remarks
- * TODO explain what this does.
- */
 export default function minimalOverride<T>(base: T, override: T): T {
   const typeofOverride = typeOfValue(override)
   if (typeofOverride === ValueType.Opaque) {
diff --git a/theatre/shared/src/utils/types.ts b/theatre/shared/src/utils/types.ts
index 927def3..59e4498 100644
--- a/theatre/shared/src/utils/types.ts
+++ b/theatre/shared/src/utils/types.ts
@@ -7,6 +7,9 @@ export type ReduxReducer<State extends {}> = (
 
 export type VoidFn = () => void
 
+/**
+ * A `SerializableMap` is a plain JS object that can be safely serialized to JSON.
+ */
 export type SerializableMap<
   Primitives extends SerializablePrimitive = SerializablePrimitive,
 > = {[Key in string]?: SerializableValue<Primitives>}
diff --git a/theatre/studio/src/panels/SequenceEditorPanel/VerticalScrollContainer.tsx b/theatre/studio/src/panels/SequenceEditorPanel/VerticalScrollContainer.tsx
index ff3db57..771303a 100644
--- a/theatre/studio/src/panels/SequenceEditorPanel/VerticalScrollContainer.tsx
+++ b/theatre/studio/src/panels/SequenceEditorPanel/VerticalScrollContainer.tsx
@@ -1,4 +1,4 @@
-import {voidFn} from '@theatre/shared/utils'
+import noop from '@theatre/shared/utils/noop'
 import React, {createContext, useCallback, useContext, useRef} from 'react'
 import styled from 'styled-components'
 import {zIndexes} from './SequenceEditorPanel'
@@ -22,7 +22,7 @@ const Container = styled.div`
 
 type ReceiveVerticalWheelEventFn = (ev: Pick<WheelEvent, 'deltaY'>) => void
 
-const ctx = createContext<ReceiveVerticalWheelEventFn>(voidFn)
+const ctx = createContext<ReceiveVerticalWheelEventFn>(noop)
 
 /**
  * See {@link VerticalScrollContainer} and references for how to use this.
diff --git a/theatre/studio/src/utils/redux/actionCreator.ts b/theatre/studio/src/utils/redux/actionCreator.ts
index 05af71c..c447173 100644
--- a/theatre/studio/src/utils/redux/actionCreator.ts
+++ b/theatre/studio/src/utils/redux/actionCreator.ts
@@ -1,6 +1,9 @@
-import identity from '@theatre/shared/utils/identity'
 import type {$IntentionalAny} from '@theatre/shared/utils/types'
 
+function identity<T>(a: T) {
+  return a
+}
+
 interface Transformer<
   Input extends $IntentionalAny,
   Output extends $IntentionalAny,