Provides expert advice on using Latex's basic formatting tools for creating all types of publications. Includes in-depth coverage of important extension packages for tabular and technical typesetting. Previous edition: c1994. Softcover.
A good reference book to learn everything you want to about LaTeX. It contains some details which are not always quite easy to find through a web search, but it obviously requires that you already know what you're looking for.
However, I can just as well recommend you start with the free e-book The Not So Short Introduction to LaTeX before you throw money into buying this book.
One of the best LaTeX reference books out there right now. It tries to cover a lot of ground, so it may not have depth in every area. It does get me on the right track almost every time. The examples in this book are quite good and more usable than other LaTeX books I have used.
I don't understand why so many people recommend this book. It is neither good for beginners nor for experts. The content is more aiming to be a comprehensive reference but it is very difficult to look up stuff whenever I need to, hence, it is not a good reference either.
I found this a great resource both when I was initially learning LaTeX and later when I was trying to use it more efficiently. The book really shines when you are trying to develop your own typesetting or to create your own sections, etc.