Errata
Page 29 - Change "Press Alt+F4." to "Activate the window, then press Alt+F4.".
Page 105 - Don't download anything from www.themexp.org. According to this report, they distribute spyware.
Page 185 - In the second tip, change "check" to "uncheck".
Page 206 - MIT no longer distributes the PGP freeware mentioned in the "Stronger Encryption Tools" sidebar. Instead try TrueCrypt at www.truecrypt.org.