Niven has created a variety of universes since his career began in 1964, but his best known is Known Space, a thousand-year future history initially strung together using the short stories he was publishing in Worlds of If, Galaxy and other SF magazines in the 1960s, and then expanded to incorporate his most famous novel, 1970's Ringworld, and its numerous sequels and prequels. Ranging from mankind's first faltering steps on Mars to his colonisation of the Solar System and expansion to the nearby stars, the Known Space stories encompass first contact with aliens, 'organlegging' (the illegal trade in human replacement organs), and even, in the case of the Gil Hamilton tales, science fictional takes on the locked room murder mystery.
I came to Known Space via an afterword in Alastair Reynolds' 2006 collection Galactic North, in which Reynolds describes how he became fascinated by future histories – and inspired to create his own – thanks to Ringworld and Niven's 1975 collection Tales of Known Space: The Universe of Larry Niven. The latter is a key book in that it not only brings together stories ranging from the earliest to, chronologically speaking, the last Known Space tale, but also boasts a Niven bibliography (to that point), a very handy timeline, and in its Ballantine first edition a cover sporting a Rick Sternbach painting depicting the 30 light-year diameter volume of space (according to Sternbach in an afterword about the cover) in which the Known Space tales are set.
As a good many of the Known Space books were published straight to paperback (in the US at least; over here more were published into hardback first), and as paperback seems to me the more natural Niven/Known Space format (reflecting the smart yet pulpy nature of the material), for the most part I've restricted myself to collecting cheap copies of those... although admittedly in multiple editions (with cover art by the likes of Peter Jones and, well, Eddie Jones). Even so, I've managed to get my mitts on some relatively scarce editions, as well as a handful of signed ones (plus some signed non-Known Space Nivens).
Thus far I've read Tales of Known Space, World of Ptavvs (1966; a typically exuberant, slightly scrappy novel in which 22nd-century humanity runs afoul of a mind-controlling alien hailing from a billion-year extinct slaver society) and The Long ARM of Gil Hamilton (1976; in which the eponymous agent of UN police force the Amalgamation of Regional Militia solves three confounding crimes – usually with an organlegging element to them – on 22nd-century Earth), and I'm partway through Protector (half of which is set in the 22nd century, the other half in the 24th). Once I've finished that, I plan on moving on to the 1968 novel A Gift from Earth (which according to the Tales of Known Space timeline is set in the 25th century, although Niven's own site begs to differ), then the 1968 collection Neutron Star (27th-century stories of 'crashlander' Beowulf Shaeffer, among other matters), and lastly Ringworld (set in the 29th century). Whether I'll fly any further into Niven's future history beyond that point remains to be seen.
