Teach yourself the Planets
David Rothery, small format  general book about all the planets, contains vital statistics and monochrome pictures, includes the moons also.

The Real Mars
Michael Hanlon, a great hardback book detailing the history of Mars exploration, also talkes about Viking, Beagle2, Sojouner, Spirit and Opportunity. 

The Case for Mars
Robert Zubrin describes how it is feasible to go to Mars today. The author is famous for his unique approach to this challenge. He is also the founder of the Mars Society, supporting manned exploration of Mars by any means possible.

The Quest for Mars
Laurence Bergreen, discussing searching for life on Mars, how to do and whats been done about it and the mission up until 2000.

Uncovering the Secrets of the Red Planet
National Geographic. Wonderful book in every way. Exciting reading, great Martian landscapes taken by sojourner. Indeed, the book is all about the sojourner story, a rover mission to Mars that cost about the same as the Movie Titanic.

Patrick Moore on Mars
Details about Mars.

Life on Mars ?
The case for a cosmic heritage ? Hoyle & Wickramasinghe. Hardback and expensive, this is nevertheless very fascinating content.

The Rivers of Mars
Piers Bizony. 

Book of the Cosmos
Scientific American. A collection of top articles and essays by leading scientists. 

The Planet Observer's Handbook
Fred W. Price. Great  practical Amateur Astronomer book. A very good book with a practical slant.