Steve's book is fascinating and a good intro to the architecture, but some of the chips used are quite obsolete (even more so that the mainstream obsolete ones!) and so building a computer from that book would be very challenging.
Huge shout out to Small Computer Central/Steven Cousins. I have four or five machines designed by him, with various main boards and backplanes. The parts are all tested working, and the build instructions are comprehensive. It’s a very enjoyable project to go from a pile of parts to connecting to the UART and blinking some LEDs.
https://z80kits.com/product-category/basekits/
https://smallcomputercentral.com/
https://j4f.info/start
http://www.searle.wales/
To name a few.
Steve's book is fascinating and a good intro to the architecture, but some of the chips used are quite obsolete (even more so that the mainstream obsolete ones!) and so building a computer from that book would be very challenging.