I recently finished reading Code: the Hidden Language of Computer Hardware and Software by Charles Petzold. Here are a few quick thoughts:
This is not really a programming book; it is a description of how computers work. Designed for the layman, it starts off with the basics of codes (Morse Code, Braille, binary codes) and then moves on to how to communicate those codes using electro-mechanical relays (such as telegraph relays). From there, it talks about how these relays can be combined in various ways to create logical operations and built up to a simple adder -- the basic building block of computer hardware. The components are pieced together from the earliest computers to modern machines (well, almost modern -- the book was written in 1999). As a non-CS major, I found this book to be very approachable and it gave me a good understanding of how software can be turned into instructions for the hardware.
Overall, this was an interesting read. For me, it went quite quickly (just a few weeks in small chunks), and I have a better feel for how computer hardware works at its most basic level.