Instruct: Classify Amazon reviews into positive or negative sentiment
Query: (Almost) everything you want

My personal favorite. I have been using both the German and the English version of this boock since 1996, and I just love it. Granted, the world has moved on, and many things about LaTeX have changed and still are, and yet, there is so much information in this book. I only hope the authors soon prepare an updated version including the latest developments.