Considering the large number of planetary missions in the last few decades it may come as a surprise that it's over 30 years since a probe had a look at Mercury - Mariner 10 in the early 1970's. Exploring Mercury, the iron planet
by Robert Strom and Ann Sprague shows that scientists with an interest in the planet haven't been idly waiting for the new Messenger mission to get there - Earth based observations together with new ways of processing the Mariner 10 data have produced plenty of new information.
Strom and Sprague show how density and magnetic field data indicate that Mercury has a surprisingly large iron core - hence the book's title. The book goes on to consider the surface of the planet - how much of it has been mapped, its composition and terrain including plains and craters. There is also a look at possible techtonic activity and a chapter on the composition of the exosphere. The book goes into considerable detail, and so is probably not for the casual reader. The book does have plenty of pictures and diagrams though, including a CD-ROM of Mariner 10 pictures, and if you are interested in the planets then you will find this book full of useful information in the run up to the Messenger mission.