Practical Advice on Creating and Maintaining Your Blog
This slim volume, by Rebecca Blood, is well-written, informative, and engaging. One of the early website creators and one of the first to use what is now considered to be the "weblog" format, Rebecca has a unique perspective on weblogs, online culture, and communication. Although I have had a weblog since 2003 (and have done a lot of reading on the subject) I learned new things from this book.
One of the most interesting things I learned is how much the idea of a "weblog" has changed since the word was coined in 1999. The earliest weblogs were information filters, "Links with commentary, with the new stuff on top".