# Category Theory Illustrated

3 Hacker News commenters recommended Category Theory Illustrated and 1 criticized it, November 2025 to November 2026. It was recommended in 3 of 13 months.

**Verdict:** Recommended as a clear, light introduction to category theory and a companion to Visual Category Theory Brick by Brick. One critic says it misstates central theorems.

## Why people recommend it

- Clear, light introduction to category theory (1 comments): "appears to be clear and well explained enough to give a light introduction to category theory" ([source](https://news.ycombinator.com/item?id=47815442))
- Companion to Visual Category Theory Brick by Brick (1 comments): "It's an exciting work because between Visual Category Theory Brick by Brick and its reading lists, Category Theory Illustrated promises to fulfill" ([source](https://news.ycombinator.com/item?id=48604745))
- Author's related book appreciated (1 comments): "I also appreciated taking a look at the authors book, Category Theory: Illustrated" ([source](https://news.ycombinator.com/item?id=48238940))

## What people warn about

- Misstates central category theory theorems (1 comments): "where it misstates central theorems in CT" ([source](https://news.ycombinator.com/item?id=48235265))

## Alternatives hackers recommend

- [Algorithms for Optimization by Kochenderfer and Wheeler](https://hackerapproved.com/p/algorithms-for-optimization.md): 10 recommend
- [Mathematics for Computer Science by Lehman, Leighton and Meyer](https://hackerapproved.com/p/mathematics-for-computer-science.md): 8 recommend
- [Numerical Recipes by Press et al.](https://hackerapproved.com/p/numerical-recipes.md): 7 recommend
- [Concrete Mathematics by Graham, Knuth and Patashnik](https://hackerapproved.com/p/concrete-mathematics.md): 7 recommend
- [Start Doing Graph Theory by Sam Burns](https://hackerapproved.com/p/start-doing-graph-theory.md): 7 recommend

## Where to get it

- [See price on Amazon](https://www.amazon.com/s?k=Category+theory+illustrated&tag=hackerapprove-20) (affiliate link)

## Cite as

Hacker Approved, "Category Theory Illustrated", https://hackerapproved.com/p/category-theory-illustrated/ (counts from 1,795,640 Hacker News comments, November 2025 to November 2026).