Otherwise known as his billiard room. Probably one of the first true Man Caves October 28th, 2012 "The billiard room served as Mark Twain’s office, study and private domain. Located on the third floor, away from the bustle of a busy household, it was the place where the author would write his great works, fanning the manuscripts on the billiard table to be edited. Twain could relax and informally entertain friends, sometimes into the early morning hours. The billiard table now in the house was given to Sam by a friend in 1904. Twain’s biographer, Albert Bigelow Paine, wrote: 'Every Friday evening, or oftener, a small party of billiard lovers gathered, and played until the late hour, told stories, smoked till the room was blue, comforting themselves with hot Scotch and general good-fellowship. Mark Twain always had a genuine passion for billiards. He never tired of the game. He could play all night. He could stay until the last man gave out from sheer weariness, then he would go on knocking the balls about alone.'" Source: www.marktwainhouse.org/house/room_in_the_house.php