Peter Gulutzan, author of SQL Performance Tuning, writes in The Full-Text Stuff That We Didn’t Put In The Manual about the particulars of word boundaries, index structure, boolean searching, exact phrase searching, and stopwords, as well as offering a few articles for further reading (Ian Gilfillan’s “Using Fulltext Index in MySQL”, Sergei Golubchik’s “MySQL Fulltext Search”, Joe Stump’s “MySQL FULLTEXT Searching”). It’s one of a number of articles in the MySQL Tech Resources collection.