As I read this book about finding life in unexpected places, I was reminded of a Star Trek episode, “The Devil in the Dark.” Kirk, Spock, and crew encounter a silicon-based life form living deep in the rock of an alien planet—totally unexpected and totally foreign. Yet, by the end of the program, the Star Trek crew come to understand the Horta, as the life form is called, and they even collaborate with it to find valuable mineral reserves buried deep in the rock of the planet. Deep Life concerns the search for life in a place where no one would expect to find life: in the subsurface rock of Earth. Author Tullis Onstott, a geomicrobiologist, writes:

We do not normally think of rock as harboring life. We quarry granite for building stone, volcanic rock for road gravel, and marble for table tops and great works of art. I would wager that the last thought on your mind as you gaze upon Michelangelo's David towering above you in the Academia Gallery in Florence is the fact that within microscopic pores buried inches beneath the smooth surface of Carrara marble are living bacteria.

The author introduces the scope of the book by posing questions related to the extent of subsurface life, the depth to which this life can be found, the lifespan of subsurface life, the possibilities for subsurface life on other planets, especially Mars, and finally the possible origins of subsurface life—where did this life come from, and how did it get there? The book begins with the discovery of subsurface life and techniques for demonstrating that subsurface organisms are not contaminants. Subsequent chapters explore some of the locales where the author journeyed to find evidence for subsurface life, such as the gold mines of South Africa. Finally, the author introduces us to some of the organisms living at great depths, such as a novel, new bacterium that lives off of radioactive decay and “the worm from Hell,” a hermaphroditic worm living one mile beneath the surface. Appendices at the end of the book provide the reader with a chronology of subsurface life investigations, summaries of U.S. DOE meetings, and a glossary of terms.

As an instructor of microbiology, I found the book to be a fascinating read. My undergraduate students would enjoy the stories of discovery and the descriptions of unusual life forms. My only reservation is that the writing is rather detailed and presumes some knowledge of biology and geology.

AMANDA L. GLAZE is Assistant Professor of Middle Grades & Secondary Science Education at Georgia Southern University in Statesboro, Georgia. In addition to science teacher education, she has taught biological science courses for grades 7 through 12 and undergraduate students over the last ten years. Her interests include evolutionary biology, science and religion, and the intersections of science and society—specifically where scientific understandings are deemed controversial by the public. Glaze holds degrees in science education from The University of Alabama and Jacksonville State University. Her address is Department of Teaching & Learning, Georgia Southern University, PO BOX 8134, Statesboro, GA 30458; e-mail: