There has been little written about the history of the Navy SEALs and their antecedents. O'Donnell (Dog Company) seeks to remedy this with his well-written chronicle of the SEAL's World War I precursor, the Maritime Unit. The unit was formed in 1942 as America's first force of "swimmer-commandos." Members of that motley crew included a dentist, a medical student, and an actor, as well as officers and enlisted men who were enemies before joining the unit. Through a combination of detective work in the National Archives and interviews with surviving members, O'Donnell successfully details the group's past, which provided the foundation upon which the modern SEALs were founded in the 1960s by John F. Kennedy. Using personal narratives, the author describes the Maritime Unit's sea, air, and land missions (the acronym for SEALs) throughout the 1940s. The epilog focuses on the experiences of unit leader and concentration camp survivor Jack Hendrick Taylor and his ongoing battle with PTSD. VERDICT This engrossing account of previously unknown World War II history will be of interest to military aficionados of all levels.—John Sandstrom, New Mexico State Univ. Lib., Las Cruces