The Golden Age of Super-Heroes began in late 1938 with the appearance of the Crimson Avenger (picture below in his later costume) in New York City, followed shortly by the first appearance of the original Flash in Keystone City, Kansas. At first thought a criminal and sought by the police, the Crimson Avenger would later prove himself to be on the side of good when he and New York's other new Mystery Man, the Sandman, joined forces in 1939 to save Britain's King George VI and Queen Elizabeth from the villainous Phantom when the royal couple were attending the New York World's Fair.
The years 1939 and 1940 saw a rash of new Mystery Men appear on the scene, several of whom banded together to form the Justice Society of America. Shortly after the attack on Pearl Harbor in December of 1941, President Roosevelt personally called together all the so-called Mystery Men (and Women) in the United States and banded them together under the banner of the All-Star Squadron. Originally, the Squadron was organized to oppose the Axis war machine directly, but Allied leaders soon discovered that Germany and Japan were both protected by powerful (and some scholars theorize mystical) barriers. Any super-powered individual who entered the sphere of influence of one of the barriers would instantly become an Axis pawn. Rather than risk having someone as powerful as Green Lantern or the Spectre suddenly join the Axis forces, or even the effect on morale should one of America's heroes switch sides, the Allied powers decreed that the All-Star Squadron would be kept away from the front lines. This decree kept the Squadron confined to Allied-controlled territory throughout most the war. Later in the war, as the Axis powers' sphere of influence dwindled, so did the barrier's effect but by the time the Allied commanders deemed it safe to allow metahuman operatives onto the front lines it was a moot point, the war was already won.
Shortly after it was founded in 1941, the All-Star Squadron established its headquarters in a building known as the Perisphere, an attraction constructed for the 1939-40 New York World's Fair. The Perisphere was a 200-foot-diameter hollow sphere that was tailored to the All-Stars' specifications by government engineers. After being damaged several times by Axis villains, the Perisphere was repeatedly rebuilt by the Squadron members themselves. Next to the Perisphere the 610-foot Trylon, also built for the fair, was altered to house the Squadron's aircraft: the All-Star Special - a modified Curtiss XP-55 Ascender with Star-rocket racer motor (designed by Squadron member Stripesy). By the time its membership reached a peak in 1942, the All-Star Squadron had more than 50 heroes. Subgroups that were a part of the All-Star Squadron included the Justice Society of America, the Seven Solders of Victory, the Freedom Fighters, and the Young All-Stars. The heroine Liberty Belle served as the Squadron's chairperson from its founding in 1941 until its disbanding in 1945.
Heroes and heroines who were members of the All-Star Squadron at one point or another included: Air Wave I, Amazing-Man I, Atom I, Black Condor I, Captain Triumph, Commander Steel, the Crimson Avenger, Doll Man, Dan the Dyna-Mite, Doctor Fate, Doctor Mid-Nite I, Doctor Occult, Firebrand I, Firebrand II, Flash I, Flying Fox, Fury I, Green Lantern I, the Guardian, Hawkgirl, Hawkman I, Hourman I, the Human Bomb, "Iron" Munro, the Jester, Johnny Quick, Johnny Thunder, Judomaster, Liberty Belle, Manhunter I, Manhunter II, Midnight, Miss America, Mister Terrific I, Neptune Perkins, Phantom Lady I, the Ray I, the Red Bee, Robotman I, Sandman, Sandy the Golden Boy, Sargon the Sorcerer, the Shining Night, the Spectre, the Spider, Starman I, Star-Spangled Kid I, Stripsey, Stuff the Chinatown Kid, the Tarantula, Tiger, the Tigress, TNT, Tsunami, Uncle Sam, Vigilante I, the Whip, Wildcat I, Wing, Wonder Woman I, and Zatara the Magician.
During the war there were four splinter groups of the All-Star Squadron which operated more or less independently. The first was the Justice Battalion (the wartime version of the JSA). The second was the Seven Soldiers of Victory, also known as the Law's Legionnaires, a group that was founded in early 1941 by the Shining Knight, the Star-Spangled Kid, Stripesy, the Crimson Avenger, Wing, Vigilante, and the Spider. Since none of its members had super-powers the group was immune to the effects of the Axis' barrier and spent most of the war protecting Great Britain. The Freedom Fighters were split off from the All-Star Squadron early in 1942 and given the task of protecting factories and shipyards on America's West Coast. Led by the enigmatic Uncle Sam, the Freedom Fighters included the Black Condor, Doll Man, the original Firebrand, the Jester, the Human Bomb, Midnight, Phantom Lady, the Ray, and the Red Bee. Finally the Young All-Stars were a group of teenaged heroes who were stationed in Denver, Colorado, and fought their fair share of Axis saboteurs and metahumans. The Young All-Stars included Dan the Dyna-Mite, Flying Fox, Fury, "Iron" Munro, Neptune Perkins, Tigress, and Tsunami.
After the war's end the All-Star Squadron was disbanded and many of its members went into semi-retirement. The Justice Battalion went back to being the Justice Society of America and its ranks waxed and waned over the next seven years, losing some old members and adding new ones like the original Black Canary (who debuted after the war, in the late 1940s). The Seven Soldiers of Victory disappeared in late 1948, thrown into different eras of Earth's past until they were rescued by the combined efforts of the Justice League and Justice Society almost fifty years after their disappearance. The Freedom Fighters remained together for a short time after the war, but they too eventually broke up as did the Young All-Stars, whose members went on to different lives and careers.
Tough many of the All-Star Squadron's members would make occasional post-war appearances, after the forced retirement of the Justice Society in 1952 most of the rest of the wartime heroes chose to retire as well, ending the Golden Age of heroes. Nearly a half-century would pass before the world would again see the number of super-heroes it had during the 1940s.