The Inter-Planetary Corporation has sent the space ship Arcturus on a routine fact-finding mission, only to have it ambushed by a strange alien craft, leaving physicist Steve Stevens and Nadia Newton first stranded on Ganymede, and then caught up in the Vorkul-Hexan war. A space adventure of staggering proportions by science fiction master writer E. E. “Doc” Smith.

In a fortuitous laboratory accident, crack scientist Richard Seaton has unlocked the secret of atomic energy. Now, partnered with his wealthy engineering-genius friend Martin Crane, he's preparing to give the world the gift of limitless, virtually free energy - and of space travel. But others want Seaton's secret for themselves.

Triplanetary was first serialized in Amazing Stories in 1934. After the Lensman series became popular, Smith took his Triplanetary story and turned it into the first of the Lensman series, using it as a prequel to give the back story for the protaganists in the Lensmen series. He added six new chapters, doubling it in size and it's really a different book from the serialized novel, being published 14 years after the first. It was put into Gutenberg just last year.

Out of the blue, a young Space Fleet officer's dream becomes reality: He's made captain of a starship. Just in time for the return of humanity's most terrible enemy, after 50 years of peace. To survive against this enemy, Captain Tad Thatcher will have to do more than learn how to become an effective commander, or how to wrangle his wayward crew. He will need to reinvent space combat. From scratch.

Welcome to Ringworld, an intermediate step between Dyson Spheres and planets. The gravitational force created by a rotation on its axis of 770 miles per second means no need for a roof. Walls 1,000 miles high at each rim will let in the sun and prevent much air from escaping. Larry Niven's novel, Ringworld, is the winner of the 1970 Hugo Award for Best Novel, the 1970 Nebula Award for Best Novel, and the 1972 Ditmars, an Australian award for Best International Science Fiction.

The war raged across the galaxy. Billions had died, billions more were doomed. Moons, planets, the very stars themselves, faced destruction, cold-blooded, brutal, and worse, random. The Idirans fought for their Faith; the Culture for its moral right to exist. Principles were at stake. There could be no surrender. Within the cosmic conflict, an individual crusade. Deep within a fabled labyrinth on a barren world, a Planet of the Dead proscribed to mortals, lay a fugitive Mind. Both the Culture and the Idirans sought it....

In 1942, Lawrence Pritchard Waterhouse - mathematical genius and young Captain in the US Navy - is assigned to detachment 2702. It is an outfit so secret that only a handful of people know it exists, and some of those people have names like Churchill and Roosevelt. The mission of Watrehouse and Detachment 2702 - commanded by Marine Raider Bobby Shaftoe - is to keep the Nazis ignorant of the fact that Allied Intelligence has cracked the enemy's fabled Enigma code. In the present, Waterhouse's crypto-hacker grandson, Randy, is attempting to create a "data haven" in Southeast Asia....

Nine hundred thousand years ago, something annihilated the Amarantin civilization just as it was on the verge of discovering space flight. Now one scientist, Dan Sylveste, will stop at nothing to solve the Amarantin riddle before ancient history repeats itself. With no other resources at his disposal, Sylveste forges a dangerous alliance with the cyborg crew of the starship Nostalgia for Infinity. But as he closes in on the secret, a killer closes in on him because the Amarantin were destroyed for a reason.

In 2108, Colony Ship Voyager departed Earth for the planet of Promissa with 18,000 of the world’s best and brightest on board. 250 years and 27 light years later, an arrival is imminent. But all is not well. The probes that they’ve sent ahead to gather the data needed to establish any kind of settlement aren’t responding, and the information they have received has presented more questions than answers. It’s a time when the entire crew should be coming together to solve the problem, but science officer Sheila Jackson can’t get people to listen.

Robert A. Heinlein wrote The Number of the Beast, which was published in 1980. In the book Zeb, Deety, Hilda, and Jake are ambushed by the alien "Black Hats" and barely escape with their lives on a specially configured vehicle (the Gay Deceiver) which can travel along various planes of existence, allowing them to visit parallel universes. However, unknown to most fans, Heinlein had already written a "parallel" novel about the four characters and parallel universes in 1977.

Extensive training molded Bruce into a finely tuned mercenary. A man capable of scouring the galaxy to protect the innocent and vanquish the corrupt. An assignment to a distant outer system brings mystery, death, and mayhem. During his mission, a chance encounter with a stunning royal in a dimly lit bar results in all hell breaking loose. Save the damsel, figure out the mystery, and kill all the bad guys. If only saving humanity was that simple.

In what is considered one of Heinlein's most hair-raising, thought-provoking, and outrageous adventures, the master of modern science fiction tells the strange story of an even stranger world. It is 21st-century Luna, a harsh penal colony where a revolt is plotted between a bashful computer and a ragtag collection of maverick humans, a revolt that goes beautifully until the inevitable happens. But that's the problem with the inevitable: it always happens.

2057. Humanity has raised exploiting the solar system to an art form. Bella Lind and the crew of her nuclear-powered ship, the Rockhopper, push ice. They mine comets. And they're good at it. The Rockhopper is nearing the end of its current mission cycle, and everyone is desperate for some much-needed R & R, when startling news arrives from Saturn: Janus, one of Saturn's ice moons, has inexplicably left its natural orbit and is now heading out of the solar system at high speed.

The totalitarian East has triumphed in a massive invasion, and the United States has fallen to a dictatorial superpower bent on total domination. That power is consolidating its grip through concentration camps, police state tactics, and a total monopoly upon the very thoughts of the conquered populace. A tiny enclave of scientists and soldiers survives, unbeknownst to America’s new rulers. It’s six against six million - but those six happen to include a scientific genius, a master of subterfuge and disguise who learned his trade as a lawyer-turned-hobo, and a tough-minded commander....

Jon Ryan was supposed to be dead. He wanted to be dead. But Jon wakes up in the far future with an alien burrowing in his chest for salvage. Someone was going to pay for this. Check that. Lots of people were going to pay for this. Jon was the first astronaut to download to an android host to find the population of doomed Earth a new home. But that was so long time ago. He is now literally lost in time.