Ask HN: What technical book did you buy and read?

I'm curious to understand what type of technical books are you still buying, and why.

I personally do not buy books, prefer to listen to audiobooks and therefore less technical subjects. For work I primarily read papers and learn about new "stuff" (languages, tools) with online docs and manuals. I also never did a technical certification.

It's a fact that the industry of technical books is in decline, and I'm sure there are opportunities to "refresh" it with new ideas and new styles of books. But before that, I was curious to understand what are people buying, are they actually consuming the content, what's the specific topic/use case.