There are literally hundreds of excellent books on volcanoes!
Some standouts off the top of my head include:
Volcano: A Visual Guide by Donna O’Meara and Professor Aubrey Manning (Paperback – Jan 18, 2008)
Volcanoes by Robert Decker and Barbara Decker (Paperback – Oct 7, 2005)
The Volcano Adventure Guide by Rosaly Lopes (Hardcover - February 7, 2005)
Volcanic Worlds: Exploring The Solar System’s Volcanoes (Springer Praxis Books / Geophysical Sciences) by Rosaly M.C. Lopes and Tracy K.P. Gregg (Hardcover – Oct 15, 2004)
Volcanoes by Peter Francis and Clive Oppenheimer (Paperback – Dec 25, 2003)
Volcanoes of North America: The United States and Canada by Charles Arthur Wood and Jürgen Kienle (Paperback – Nov 27, 1992)