James Holland's new book, Dam Busters: The True Story of the Inventors and Airmen Who Led the Devastating Raid to Smash the German Dams in 1943, dramatically details the circumstances of this terrifying, improbably successful military operation.Holland, author of numerous bestselling military history books including Fortress Malta (2004) and Battle of Britain (2011) as well as nine works of historical fiction, begins his fast-paced story in January 1943. Barnes Wallis, 52-year-old assistant chief designer at England's Vickers Aviation, is screening a film of his new invention to a group of arms manufacturers and Royal Air Force officers. It shows a 46-inch-diameter ball being dropped, spinning from a Lancaster bomber flying over water at around 290 mph at a height between 40 and 70 feet. The sphere hits the water and bounces along several times, as would a flat flung stone, until it finally comes to rest 1,100 to 1,200 yards later.This new weapon was designed by Wallis not only as a method to get past the enemy's protective torpedo nets in order to strike at German warships anchored in Norwegian fjords, but also to blast German dams and thereby destroy the German defense industry, a plan that is the subject of this book.As the author makes clear, it was a Sisyphean task on Wallis' part to translate his wildly unconventional "bouncing bomb" idea into reality. Design details, endless experimentation, complex bomb-spinning apparatus incorporated into planes and special crew training all had to be completed in less than 10 weeks when, in May and June 1943, the water behind Germany's dams would be at its highest. What made Wallis' undertaking even more difficult, Holland informs us, was the furious resistance to his innovations from Britain's Bomber Command leader, the bull-faced Air Marshal Arthur Harris, who resoundingly referred to them as "tripe of the wildest description. There are so many ifs and buts that there is not the smallest chance of it working." Yet, miraculously, Wallis' idea won out. On the night of May 16, 1943, 19 RAF Lancaster bombers, each carrying a 4-ton cylindrical bomb, took off from Lincolnshire in two waves. They flew insanely low — under 100 feet! — to avoid flak, skimming trees, dodging power lines. Even birds were a danger. Their targets: Germany's three massive hydroelectric dams: the Mohne, the Eder and the Sorpe. What follows, as Holland dramatically describes, is one of the great adventure stories of World War II.Before the low-flying planes even reached their targets, enemy flak put out communication and compass capabilities on one of them, forcing it to turn back. Another low flyer, damaged and losing its bomb when the plane actually smacked the surface of the North Sea, had to do the same. And, tragically, 32-year-old Canadian Capt. Vernon Byer's K-King, hit by flak, plunged burning into Dutch swampland, killing everyone aboard, writes Holland. Two more bombers hit power lines, killing their crews. The remaining 14 Lancasters were now within sight of the first dam to be attacked, the Mohne. Under ferocious flak 24-year-old Squadron Commander Guy Gibson's G-George was making its attack run at the dam, practically skimming the water. He dropped the bomb spinning from the plane at an incredible 500 rpm. It bounced along the lake, hit the dam, sank and then "a sudden huge explosion and a massive column of water towered some thousand feet into the sky," relates Holland. Another attacking bomber, 22-year-old John "Hoppy" Hopgood's M-Mother, dropped its bomb, but it bounced right over the dam and onto the power station 200 feet below, blasting it to pieces. Hopgood's plane, hit by flak, was aflame. Three crew members parachuted to safety; the others died. After several more strikes on the Mohne — with Flight Lt. David Maltby's J-Johnny's hit sending up "not just water but mud and stone as well" — the dam simply gave way, sending hundreds of millions of tons of water down the Ruhr Valley, killing huge numbers of people in a tsunami of water and debris, and setting back Nazi Germany's warmaking timetable. The same thing happened at the Eder Dam. The Sorpe was structurally weakened. Holland's Dam Busters, thrilling, authoritative and containing astonishing photos, is a military history "must read." It is also a shining tribute to those intrepid young airmen.