“This is the 6th volume in Salem's Principles of… series. (The other volumes cover chemistry, physics, astronomy, computer science, and physical science). An encyclopedic work, it contains 112 articles, alphabetically arranged by subject from Activation Energy to Zoology. Each entry includes a list of fields of study, a brief summary of the topic, principal terms, two to seven pages of text, and a bibliography, sometimes descriptive, of four to six books or periodical articles. Most entries contain black-and-white illustrations. Some entries include graphs, websites, and a sample problem. Also included are a twelve-page glossary, a list of Nobel Prize Winners in Biological Studies from 1996 to 2016, two illustrated pages of body systems, a descriptive bibliography of more than four hundred items, and a subject index. Contributors are listed for most of the articles, usually without affiliation. The editor, Christina Crawford, is Assistant Director for Biology and Life Sciences of the Rice Office of STEM engagement.