J. R. R. Tolkien
John Ronald Reuel Tolkien is the author of several books which practically started the genre of high fantasy in the 20th century. While Tolkien lifted his material heavily from Germanic (particularly Nordic and Anglo-Saxon), Celtic and Finnish folklore, the stereotypes that he established last to this day, especially in fantasy gaming. It is probable that without his works the hobbies of roleplaying and fantasy gaming would not exist today as they do, along with a shitload of bad fantasy novels written by talentless hacks trying to emulate his works (admittedly they would have just ripped off someone else if Tolkien had not existed).
The most well-known works by Tolkien include:
One of the main themes of The Lord of The Rings, and Tolkien's miscellaneous writings, is industry vs. nature, with industrialists being portrayed as a bunch of greedy pricks (e.g. Saruman) and rural types being portrayed as decent, "salt-of-the-Earth" people (e.g. Samwise Gamgee). He was a giant romantic (see Beren and Luthien and how he met his wife), cool as hell, awesome (notably telling off Nazis by explaining to them that their whole 'Aryan' thing was a crock) and that was pretty much the way most people were back then. Every inch a scholar and a gentleman.
About his writing: Tolkien liked to take his sweet time with things. This can either be a blessing (bringing up details about the world he has created and helping immerse yourself in it) or a hindrance (bringing the story to a standstill) depending on how you view it.
Tolkien was also big on pipe smoking. His favourite pastime could be felt in his books, where pipe smoking among various characters is described in a colourful detail. In every situation, where characters were relaxing or having fun, they were no doubt pulling away on a finely-crafted smoking pipe.