Bolker's book has been my bible for the past couple of years. It is essential in providing that "you're not alone" awareness that every graduate student needs, using simple language and a sense of humor to outline the commonest stumbling blocks on the way. Although there's no way one can really complete a dissertation in "15 minutes a day" (the author herself admits it's just a marketing trick to catch your attention), it is quite possible to start at 15 minutes a day, and build it up gradually. It is the best of the three or four books on the subject I purchased, and I keep going back to it. A perfect gift for someone writing a dissertation.