If you are getting started in the tropical fish keeping hobby, this would be a good book to have on hand. The title is "The Simple Guide to Freshwater Aquariums" by David E. Boruchowitz, and there is a lot of helpful advice within its 243 pages.
The book goes into detail about setting up a basic system, how to cycle your tank, what kinds of fish to choose and how many, filtration, maintenance, lighting options, planting, feeding, disease, temperature variation, water quality, combining species, etc. There are a load of color photos, too.
The author of the book, David E. Boruchowitz, is the Editor in Chief of Tropical Fish Hobbyist magazine, so he knows what he is talking about. He also keeps fish himself.
This is an informative, educational book on fish keeping, especially good for anyone who is new to the hobby. I would definitely recommend it.