When I first saw this book advertised, I thought it would be a painless way to fill in the gaps in my knowledge, e.g. in quantum computing and information theory. It indeed has a very wide sweep, an engaging style that is very clear and moves the reader along, an attractive design, and many other good points. I haven't checked all the math, but Gershenfeld seems most at home with theory.
The problem is that when he touches on something I really am expert in, he falls on his face much too often. I don't mean just that he oversimplifies and leaves things out--how could he not--but that the book is full of genuine factual misinformation. Some representative examples: In 3.1.2, he confuses deterministic and stochastic processes completely, a confusion that persists throughout the extended discussion of noise; in 3.3.1, he says that shot noise dominates only for small arrival rates, whereas in reality it is dominant only in the limit of large rates; in 10.3, he's wrong about how bipolar transistors work, and wrongly says that their base current is why they aren't widely used in logic anymore; in the preamble to Chapter 12, he says that hard disk drives use "basically rust" to store information, whereas they've used plated metal for years, and that recording heads fly at 1 micron, whereas it's 50-100 times closer than that (120-200 angstroms). His discussion of modems wrongly says that 50kb/s+ modems rely on data compression for their speed, whereas the discrepancy is his underestimation of the S/N ratio of a good phone line.
And (most embarrassing of all for a theoretician) in his discussion of special relativity, he goes through a long derivation of the kinetic energy of motion, but makes an elementary integration error in the last line in order to (wrongly) display the famous mc**2.
Gershenfeld is clearly a very able guy who knows a lot about the physics of information technology--but I'd trust the book a lot more if I didn't keep tripping over these sorts of things. Let's hope the second edition is more carefully done.