Introduction to Astrobiology
As you probably know, astrobiology, the study of extraterrestrial life, is still a largely theoretical discipline No life has been proven to exist, although there are some tempting hints on Mars and perhaps on Jupiter’s moon Europa along with other bodies that have internal oceans. Currently the bulk of work in Astrobiology is concerned with characterizing the conditions under which some form of life might thrive and study various environments that may meet those criteria. That’s why many of the missions to Mars focus on finding water. Life as we know it requires water. In our current view, no water = no life. Incidentally, this hypothesis means that either the writers of the movie “Signs” either made a serious error (aliens destroyed by regular water) or that the aliens of “Signs” would be identified by Mr. Spock as “Life, but not as we know it at all.”
If you’re searching around the ‘net for additional materials in this area, using the term exobiology might be helpful. That term is more likely to bring up earlier work. If you’re searching in library catalogs using a subject search, looking for exobiology should direct you to astrobiology.