If you really want to learn the craft, this is an outstanding book. If you want to learn some quick wins, pick another book.
Unfortunately I have not read the second edition of this book which was released 2008. But since it is the same writer and basically the same book, just updated, I think what I'm going to write here is still valid.
Ron Brinkmann, the author, has selected an interesting cover for the book, because it is an early example of compositing, long before computers. With someone looking like Virgin Mary as the center image of the cover it I was sort of repelled before I knew what kind of image it was.
Wikipedia says that compositing is the combining of visual elements from separate sources into single images; this often to create the illusion that all elements are parts of the same scene.
The moment you use a green-screen when you film, you will use compositing to get it all together.
In my graphic novel project I use it all the time, since I paint the background and all the characters on different pages and merge them all together in the computer.
The Art and Science of Digital Compositing is not what I usually label as a "typical-American-five-steps-to-do-something" book. This has a more boring and stiff appearance. The contents is however far from dull. The writer explains very carefully and in a way easy to understand how compositing works. It starts with the basics with the idea that you have never done this before and continues on.
It starts out with still photos. This is about the first half of the book. In the second half what was taught in the first half is applied to moving images.
You'll quickly understand that there are no fast tricks to do this, just patience and skill.