I bought this book for a college course in computer architecture, and the exersizes in it are *exactly* what you need to get the most from a PC architecture/microprocessors course. We used this in addition to another text, but most of the course (and nearly all of the lab time) was spent on microprocessors, anyway.
This book is intended to be both textbook and workbook (I think), but that's not the way we used it.
In any case, "Heathkit" is a brand of microprocessor "trainer" -- basically a CPU with typical instruction set, plus programs which allow it to be controlled by a keyboard. The CPU, memory, and keyboard are all attached to a unit with LED display and lights, so you can give the CPU instructions and see the contents of any register. This is further expanded by attaching various types of logic gates (geek-speak for certain types of circuits) which produce output based on input. This is how information and instructions are relayed to other parts of the computer, and it's also how you can simulate the logic design of a computer program (which produces logical output from input).
What I loved best about these exercises, is not only understanding the microprocessor (CPU), but also the ability to simplify BINARY (as opposed to algebra) equations, which I immediately saw could be applied to more complicated programing questions in websites or software! (Math is simpler to deal with than imagining the combination of reponses to questions, especially if they involve text, but the POSSIBLE COMBINATIONS essentially boil down to math, can therefore be simplified the same way.)
Binary equations just look like funny algebra, and simplification is simliar, except that you are likely to confuse the rules at first because the notations look similar and "jargon" (such as "ANDING" and "OR") sometimes mean different things. You're tempted to follow the algebra rules and it takes a bit to get them straight in your head.
Actually SEEING your equations at work (by choosing the logic gates, connecting the gates with wires, and watching the resulting lights indicating the output) brings these logic problems to life!
Even if you don't intend to become an engineer, but rather a programmer, security specialist, or power-user of computers for work or other heavy purposes, you will appreciate the understanding this gives you of how CPUs work (and how memory can be corrupted, since there are Heathkit exercises where you do this on purpose). It just makes *sense* when you see a CPU cycle diagramed, following the data around, and when you put this knowledge to work solving math and other problems!
The computer architecture course using this book was the only true "engineering" class I took, and I'm not counting a basic PC hardware course as engineering. A wonderful book!