An interesting discussion into how various environments on exoplanets could shape the evolution and behavior of extraterrestrial life. However, many readers will be discouraged by the lack of physical descriptions of that life, as well as the authors' hesitation to consider the wildest ideas about life that human imagination has brought forth.

I would have liked to see a discussion of the more scientifically grounded alien life forms in popular science fiction, as well as a discussion of the strange forms of life "really not like us" (the authors' term) present here on earth (e.g. fungi, insect colonies).