You Don't Know JS Yet: The Unbooks

by Kyle Simpson

You Don’t Know JS The Unbooks is a special, draft-edition release collecting the final remaining content from the second edition of the You Don’t Know JS Yet series. It includes the complete, previously unpublished drafts of Book 3: Objects & Classes and Book 4: Types & Grammar—books that were written in full but never formally edited or released for publication.

These chapters reflect the same in-depth exploration and care you’ve come to expect from the series, just presented here in their raw, unedited, unpolished form. They’re readable, structurally complete, and technically solid—offered honestly as-is.

This release also includes two bonus chapters on the “lost” volumes that were never Book 5: Sync & Async and Book 6: ES.Next & Beyond. These reflective essays explain what those books were meant to be, why they were ultimately abandoned, and what insights remain worth sharing. This is a project for the completists, the curious, and anyone who still cares deeply about understanding JavaScript, not just using it.

432 pages, Kindle Edition

Published May 4, 2025

About the author

Kyle Simpson is an Open Web Evangelist from Austin, TX, who's passionate about all things JavaScript. He's an author, workshop trainer, tech speaker, and OSS contributor/leader.