Flann O'Brien (born Brian O'Nolan) penned five volumes of fiction under this name. There is a great biography written about him in Murphy and MacKillop, Irish Literature: A Reader, Syracuse: Syracuse University Press, 1987. At Swim-Two-Birds and The Third Policeman are the most popular of his works.
Excerpt from At Swim-Two-Birds,
"There are two ways to make big money, he said, to write a book of to make a book.
It happened that this remark provoked between us a discussion on the subject of Literature--Great authors living and dead, and character of modern poetry, the predilections of publishers and the importance of being at all times occupied with literary activities of spare-time or recreative character. My dim room rang with the iron of fine words and the names of great Russian masters were articulated with fastidious intonation. Witticisms were canvassed, deepening for their utility on knowledge of the French language as spoken in the medieval times. Psycho-analysis was mentioned--with, however, a somewhat light touch. I then tendered an explanation spontaneous and unsolicited concerning my own work, affording an insight as to its aesthetic, its daemon, its argument, its sorrow and its joy, its darkness, its sun-twinkle clearness (Murphy and MacKillop, Irish Literature, 317)."