Last week Macworld posted my article Fix Mac slowdowns, in which I take inspiration from Take Control of Troubleshooting Your Mac to discuss numerous potential ways to deal with a Mac that's become more sluggish over time. The article includes some tips not in the book and vice-versa, though a number of common troubleshooting steps appear in both places - restart your Mac from time to time, add more RAM, keep software up to date, and so on. The Macworld article goes into more detail about speeding up email clients and Web browsers that have lost their zip, among other things.