One of my biggest regrets is the decision 30 years ago to give away all my programming reference books, assuming I'd never need/want them again. I've been looking out for this one for a couple of years now: it's like the proverbial hen's teeth. Whilst it's not as influential as the seminal "Programming the Z80" (Rodney Zaks), it is the book I could afford as a 15-year old, and served me well for a few years, developing games on the ZX Spectrum and Amstrad CPC.

Anyway, was checking on the progress of an order on Amazon and threw up a search and there was a copy for sale on World of Books (Amazon Marketplace) for £3.20. Kerching!

So I'll own the holy trinity of books that got me into assembly language programming:

- Mastering Machine code on the ZX80/81 by Toni Baker
- The Complete Spectrum ROM disassembly by Frank O'Hara and Ian Logan
- That

I'm doing my happy dance now.

@breakintoprogram I have started filling out my own collection of retro programming books. I got the Amiga ROM kernel manuals for the first two revisions, along with a bunch of other random books, and they're great. I also have the first book I worked through to learn how to program the Commodore 128.
@TopazRabbit Grand! You can't beat a good book collection. I don't know about you, but it's quite interesting going back to the books with (in my case) 40-odd years of experience.