You might want to just do some research into programming languages and various hardware parts.

Computers cover everything: Electronics, physics, algorithms, etc.

I doubt a single book would teach you everything about a computer, because it's so broad. It might give you some labels and concepts, but for a really deep understanding, you need to branch off into electronics, physics, programming languages and compilers. To understand how computers communicate over a network, you might need a certain book for that as well.

A computer has had input into it from a diverse range of complex fields.

For example.

You can probably just hit up Wikipedia and type in: harddrive. Then type in RAM. You can then learn how and why there are 2 types of memory, and how the memory in the hardrive is 'trucked' into ram, and why.

But remember, it's very complex. Take the computer screen. You can learn about that type of technology as well.

There's a lot to a computer. It's taken for granted by many.