Tellus is the name given to Earth by most characters in the Lensman series, although it is also occasionally referred to by other names, including Earth, Terra and Sol III. As the most powerful of the founding worlds of the Galactic Patrol, it is home to that organisation's headquarters, Prime Base. An average world in the setting, it provides on average one hundred new Lensmen every year, as well as several tens of thousands of Galactic Patrol enlisted men and officers per year at the very least, and built eighty superdreadnoughts as its contribution to Grand Fleet when the invasion of Lundmark's Nebula was being planned.
As one of the four main Arisian breeding program sites, Tellus has had a long and particularly troubled history, owing to covert attempts by the Arisians and the native humans to build up civilisation in the teeth of Eddorian attempts to destroy it. The first civilisation upon it to achieve atomic power, that of Atlantis, was wiped out by a nuclear war that also caused enough damage to submerge the Atlantean continent.
Eddorian interference also results in, amongst other things, the First, Second and Third World Wars, the last one apparently being set some time in the 20th Century and involving a nuclear exchange between various communist regimes (likely working together under the Tyrant of Asia) and the Western world. However, Western anti-ballistic missile defences were sufficient to protect a large portion of the West, and allowed humanity, with a lot of secret assistance from the Arisians, to recover remarkably quickly.
Following the three World Wars, humanity expands into space, forming relations with the Venerians and Martians. However, Eddorian interference once again results in several new wars - this time against the Jovians, particularly the so-called Adepts of North Polar Jupiter. Unfortunately for Eddore however, the three inner planets unite to form the Triplanetary League and win the Jovian Wars, forcing Gharlane of Eddore to turn instead to piracy and the persona of Grey Roger to bring down this new political entity, by the time of Virgil Samms in Triplanetary.
Tellus In Civilization
Tellus has a prominent place in Civilization, being the headquarters of the Galactic Patrol and a founding member. It was under heavy surveillance from a Boskonian base on Neptune for some time, and was very nearly destroyed in the Battle for Tellus. Most of the major human characters also appear to have come from Tellus, although given the Arisian breeding program there this is perhaps not entirely unexpected.
Humans in Civilization
Humanity has managed to develop upon many different worlds through the two galaxies (most likely due to Arisian life spores), and they are described as the leading species of Civilization, as opposed to the Eich of Boskone (although many humans do work for Boskone). The defining racial characteristic of humanity though is immensely strong willpower or drive, making them difficult targets of telepathic control and the like compared to, say, the Velantians.