# Undocumented DOS by Andrew Schulman

3 Hacker News commenters recommended Undocumented DOS by Andrew Schulman and 0 criticized it, November 2025 to November 2026. It was recommended in 3 of 13 months.

**Verdict:** People recommend it as a deep reference on undocumented DOS internals, valued enough that readers call it a bible for months of work.

## Why people recommend it

- Deep reference for DOS internals (1 comments): "I remember the books on undocumented functionality like" ([source](https://news.ycombinator.com/item?id=45945037))
- Read as a core reference (1 comments): "they've been my bibles for the past several months" ([source](https://news.ycombinator.com/item?id=49294456))
- Treated as essential sacred text (1 comments): "have literally been my religious texts" ([source](https://news.ycombinator.com/item?id=49823499))

## Alternatives hackers recommend

- [Crafting Interpreters by Robert Nystrom](https://hackerapproved.com/p/crafting-interpreters.md): 60 recommend
- [Clean Code by Robert C. Martin](https://hackerapproved.com/p/clean-code.md): 31 recommend
- [The Pragmatic Programmer by Hunt and Thomas](https://hackerapproved.com/p/pragmatic-programmer.md): 28 recommend
- [How to Design Programs by Felleisen, Findler, Flatt and Krishnamurthi](https://hackerapproved.com/p/how-to-design-programs.md): 18 recommend
- [Mastering Emacs by Mickey Petersen](https://hackerapproved.com/p/mastering-emacs.md): 17 recommend

## Where to get it

- [See price on Amazon](https://www.amazon.com/s?k=Undocumented+DOS+by+Andrew+Schulman+et+al.&tag=hackerapprove-20) (affiliate link)

## Cite as

Hacker Approved, "Undocumented DOS by Andrew Schulman", https://hackerapproved.com/p/undocumented-dos/ (counts from 1,795,640 Hacker News comments, November 2025 to November 2026).