Armageddon 2419 A.D. (1928) by Philip Francis Nowlan

Wikipedia wrote:Armageddon 2419 A.D. is Philip Francis Nowlan's novella which first appeared in the August 1928 issue of the pulp magazine Amazing Stories. A sequel called The Airlords of Han was published in the March 1929 issue of Amazing Stories.

Wikipedia wrote:Nowlan’s novella tells about America in the 25th century, conquered by Hans in 2109 AD and only now beginning to rebel. Sometime after World War I, nearly all the European powers joined forces against the United States. Although the US won the war, both sides were devastated by the conflict. Taking advantage of the chaos that followed, the 'Russian Soviets' (USSR) joined forces with the 'Mongolians' to take over Europe. The US collapsed economically and stagnated while the 'Mongolians' turned against the Russians and defeated them as part of their campaign of world conquest.

American efforts to avoid war with the 'Mongols' failed and in 2109 AD, they attacked the US using fleets of airships armed with disintegrator rays. They attacked from the Atlantic and Pacific coasts and down from Canada. After conquering the US and Canada, these 'Airlords of Han' ruled North America as a province of the world empire from fifteen great cities they established across the continent. They ignored the Americans who were left to fend for themselves in the forests and mountains as their advanced technology prevented the need for slave labor. From time to time, they raid American land "to keep the 'wild' Americans on the run within the shelter of their forests, and prevent their becoming a menace to the Han civilization."

Living in cooperative gangs and hiding in the forests from the Hans, Americans secretly rebuild their civilization and develop the new technologies "ultron" and "inertron". Inertron is a substance with "reverse weight" (anti-gravitational properties), so that a person carrying an amount of inertron equal to most of his weight (in the form of a “jumper” – "rocket motors encased in inertron blocks and strapped to the back") can travel rapidly across country in long leaps. Ultron, in turn, is an "absolutely invisible and non-reflective solid of great molecular density and moderate elasticity, which has the property of being 100 percent conductive to those pulsations known as light, electricity and heat."

Wikipedia wrote:Predictions of future technology
Despite being written prior to World War II, the story line accurately foreshadowed several notable advancements in technology and military theory & practice. These include:

Remote piloted surveillance and attack drones.
Immersive Telepresence
Telecommuting
Consumer E-purchasing
Paratroopers
The shortcomings of an air supremacy war without concomitant ground forces (proven in the Vietnam War)
Night vision devices
Bazookas
Optical devices for Small arms such as the Reflector sight and Red dot sight.
Wireless phones

Wikipedia wrote:The main character and the narrator in Armageddon 2419 A.D. is Anthony Rogers, who later appears in the various comic strips, radio shows, and film serials that follow as "Buck Rogers". Rogers recounts the events of the “Second War of Independence” that precedes the first victory of Americans over Hans, in which he plays an important role.

Born in 1898, he was a veteran of the Great War (World War I) and was by 1927 working for the American Radioactive Gas Corporation. He was investigating reports of unusual phenomena in abandoned coal mines near Wyoming Valley in Pennsylvania. On December 15, while investigating one of the lower levels of a mine, there was a cave-in. Exposed to radioactive gas, Rogers fell into "a state of suspended animation, free from the ravages of Katabolic (sic) processes, and without any apparent effect on physical or mental faculties." Rogers remained in “sleep” for 492 years.

He awakes in 2419 and, thinking that he has been asleep for just several hours, wanders for a few days in unfamiliar forests (what had been Pennsylvania almost five centuries before). He finally notices a wounded boy-like-figure, clad in strange clothes and moving in giant leaps, who appears to be under attack by others. He defends the person, killing one of the attackers and scaring off the rest. It turns out that he is helping a girl, Wilma Deering, who, on “air patrol”, was attacked by an enemy gang, the "Bad Bloods", which is presumed to have allied themselves with the Hans.