It was a nice overview, but it lacked some substance. The sidebars were entertaining, but lacked detail. There was mention of a cipher to do with Richard Feynman, but no details at all as to where to find it.

The PKE section was quite good. I never really had a handle on how that worked and I get it now.

The sections about quantum mechanics and communications were quite lame. I think it would have been better to just allude to them rather than try and give a simplistic view of Quantum Mechanics mention the wave collapse and call it good.

All in all a good quick read. Maybe even better suited for high school students.