_Build Your Own Z80 Computer_ by Steve Ciarcia is fantastic. You will learn the basics of computer architecture, digital logic, assembly language, power supply design, and a basic operating system. Even though it's a book from the early 80s using chips from the late 70s the parts are still available.I believe the author has posted a pdf of the book on his website, but there are used copies on Amazon and Ebay and it's a lot of fun doing a project like this without using the internet by relying on nothing but the paperback and a mouser catalog. https://www.amazon.com/Build-Your-Own-Z80-Computer/dp/007010... https://archive.org/details/BuildYourOwnZ80ComputerSteveCiar...