Awareness of the environment was stimulated by the 'Earthrise' pictures taken by the first Apollo crew to orbit the Moon. By sending spacecraft to other planets we've gained insights into the early history of our own planet. Comparative planetology is a science that has been facilitated by the Space Age. Comparative planetology highlights both similarities and differences. Processes tend to manifest themselves in different ways. Usually the term 'vulcanism' conveys an impression of red hot lava erupting from a fissure, or streaming down the flank of a volcano. This may have been the case on Venus and Mars, but on some of the Moons of Jupiter and Saturn the lava is cryogenic fluid. There are geysers of sulphurous gases on Jupiter's moon Io and at the far edge of the solar system on Neptune's moon Triton, there are Nitrogen geysers. Our concept of vulcanism has been broadened by comparative planetology. The Earth in Context: A Guide to the Solar System tells a tale of scientific discovery, with two interwoven strands - one tracing the development of understanding the Earth's geological history, and the other placing this in the context of processes at work on the other planets of the solar system. Although planetology is assigned half of the text, the primary focus of the book is the Earth. It is discussed in two parts, the first summing up our knowledge of the Earth as it is today and the other considering it as it was long ago.
From the reviews of the first edition:
"This book is a very comprehensive examination of all of the planets and main planetary moons of the Solar System with an emphasis on internal structure. ... the book is a very good starting point for anyone interested in the study of the solar system and in particular to geologists with such an interest." (Emlyn Jones, Astrology & Space, August, 2003)
"David Harland is well known for his previous books ... . Those books were very popular due to their well-written and well-illustrated text, and this one is no different in those respects. ... The main readership to benefit from this book might be first-year undergraduates with an interest in planetary science ... . The main attraction of this book is the way it is written. It is extremely easy to read, making the progress of assimilating information a pleasure ... ." (Sarah Dunkin, The Observatory, Vol. 123 (1173), 2003)