Noam Nisan and Shimon Schocken's The Elements of Computing Systems good starting point for various topics - It's the accompanying book to their Nand2Tetris cour

Noam Nisan and Shimon Schocken's The Elements of Computing Systems good starting point for various topics - It's the accompanying book to their Nand2Tetris course and, along with my explorations with the Raspberry Pi, was one of the starting points in my computing exploration.