I'll add another vote for it. It's a well-done entry in the sparsely populated but useful genre of fairly-but-not-too-technical computer books. Less technical than a book on computer architecture intended for a computer engineer; but more technical than the almost insultingly introductory "how your computer works!" type of books.

I think "Security Now" is a podcast example of this balancing act. Though like most TWiT podcasts, it's fluffed out to twice the length it should be.