In the early pages of "Vanished," Wil S. Hylton writes that the number of American troops missing in the Pacific Theater of World War II is comparable to total U.S. casualties in Vietnam, a staggering number that architect Maya Lin has made easy to visualize. This gives scale to the topic Hylton has chosen for his book — the attempts to find some of those 56,000 troops.

The man at the center of the book, Pat Scannon, does it as a hobby. His day job is in biotech. In the early 1990s he and a friend went on a scuba diving trip to Palau, an island between the Philippines and Papua New Guinea. The muddy waters around Palau aren't known for spectacular viewing, but rumors of lost treasure lure divers. Scannon finds a World War II plane's propeller, and can't stop thinking about it. Over the next 20 years he does (and continues to do) exhaustive research to piece a puzzle together and reconstruct a decades-old battle. He explores the waters for more remnants, talks to islanders who were there, combs military archives for photographs and reports. His main interest is in the people, not the planes or battle plans, so he attends military reunions and meets widows and children of the airmen involved. He wins the respect and help of the military, and starts a group with a lofty goal: "to repatriate every American service member who has not come home."

Although "Vanished" would not be possible without Scannon, it is not strictly his story. Hylton takes time to give deft portraits of many of the airmen themselves, recounting their final days and hours, as well as the Japanese combatants on the other side of the battle. He tells the stories of parents, wives and children who suffer the "ambiguous loss" of loved ones missing in action, including a boy who grows up hearing rumors that his father is alive halfway across the country.

In one haunting passage, Hylton tells the peculiar postwar life of one of the survivors. He also gives time to other key figures in the search and recovery, particularly Eric Emery, an underwater archaeologist who oversees the expeditions to exhume and identify remains and restore them to their families.

Hylton is at his best with profiles, making people knowable in a few pages by focusing on their definitive moments. Though he includes the hard data and trivia likely to entice a World War II buff — mechanical details of bombers, explanations of how one fatal mission figured into the greater U.S. military strategy, cameos by Bob Hope and Charles Lindbergh — it is his humane approach to the topic that makes "Vanished" remarkable. Readers feel, in the final chapters, a real loss for men they knew at the outset were going to die, and profound gratitude to those who bring closure to their families.

Minneapolis writer Kurtis Scaletta received the Readers' Choice prize at the Minnesota Book Awards in 2012.