A Harvard graduate and an air-and-space writer, James Chiles has chronicled the triumph of physics, engineering and imagination that made the helicopter "a wondrous invention."

"The God Machine" is a well-researched history of the helicopter, including the personal stories of such quirky characters as the original inventors — two Frenchmen named Launoy and Beienvenu — who flew their machine for the French Academy of Sciences in 1784. And Igor Sikorsky, who invented the first production helicopter that revolutionized war in 1958.

Probably most important, the helicopter revolutionized rescues of people worldwide by extracting people from virtually any predicament. In 2005, 35,500 people were lifted from the disaster of Hurricane Katrina.

The author includes many drawings and illustrations in an effort to explain the engineering of the helicopter. "Any functional helicopter," he writes, "must have rotors for lift and control, some kind of engine, a mechanism for controlling altitude and direction, and a frame to hold everything together."

He discusses the five types of helicopters: the single main rotor (the most common, to include news helicopters, medical helicopters and personal helicopters), the coaxial, side-rotor, tandem and intermeshing. Chiles explains all of them in detail.

In its simplest form, the main part of the helicopter "is an airplane fuselage with an unpowered rotor on top, angled to catch the wind when moving forward." Although the earliest models also had "stubby airplane-like wings" to provide control for the pilot, it was soon learned that the only necessary wings were those spinning on top. The wings are shaped in such a way as to create lift.

The author discusses some of the best-known rescues carried out by helicopter. The first was the rescue of a civilian in April 1944, when a Coast Guard R-4 Hoverfly picked up a teenager stranded on a sandbar in New York's Jamaica Bay. Sikorsky said, "If a man is drowning in the ocean, an airplane is only good for tossing him a funeral wreath. But a helicopter will bring him home."

The most remarkable helicopter publicity came when Lyndon Baines Johnson, Texas congressman and future U.S. president, used a helicopter to campaign for the U.S. Senate. He was looking for a way to be noticed — and very few people at the time had seen a helicopter. Johnson's so-called "air assault" began on June 15, 1948, when his helicopter dropped into a softball field in Terrell, 30 miles east of Dallas.

There were 500 people waiting to listen to the politician speak. Just before landing, Johnson threw his $25 Stetson hat into the crowd.

Afterward, LBJ "ascended into the heavens" and spoke to seven more groups of people. Within a week, LBJ had narrowed the lead of his opponent, Coke Stevenson, from 36 points to 10. LBJ's brother, Sam Houston Johnson, said he heard a farmer say, "If he can keep that damn thing from chopping his head off, he might make a good senator."

Johnson also used the helicopter to drop in on suburban shopping centers in Houston, Dallas and Fort Worth.

He ended up winning the election.