Homebrew CPUs/Low Level Design
I can recommend two books aimed at learning digital logic:
Fundamentals of Logic Design by Dr. Charles Roth
This book is intended as a textbook for a self-paced first-year undergraduate class on logic design, and is broken up into several small chapters with self-study parts and problems at the back. In the introduction, there's a recommended order for the chapters. Some of the chapters are optional, but I'd make sure to do Appendix B (IIRC) which covers digital input and output circuits, which you will need to deal with.
TTL Cookbook by Don Lancaster
If you're going old-school, this is the old-school book you want. Written in the 70's, it focuses on 74xx series TTL logic, culminating in a project to build several circuits for a &quot;TV Typewriter&quot;, which just lets you type on a TV set. (I mentioned old school, right? This was when 8-bit microcomputers like the Apple II were hundreds of dollars, not some $10 Arduino.)
Don Lancaster also wrote a CMOS Cookbook if you want to use the even slower 4000 series CMOS logic, which can run on voltages from 5 to 15 V, but leads to 5V HCMOS logic, which leads to modern low-voltage, high-speed CMOS.
The main difference between these books is that FoLD will give you the EE-grade tools to do it right (like using a Karnaugh map to work out the optimal next-state logic for a state machine, which you can then map to a PAL, GAL, or discrete logic), while the Cookbooks focus on all the tricks to make your life easier (like using a bunch of 1-of-16 encoder/multiplexers to encode your combinational logic so you just have to rewire a few pins to fix bugs; bigger chips, but easier debugging).
Once you have this down, the Computer Architecture books will make a lot more sense because you'll look at it and know what a register, adder, subtracter, multiplier, state machine, and tri-state bus are, and parts like instruction decoders and load/store units won't be as scary because you'll know how to break large design blocks down into smaller state machines.