To the popular press, “hacker” means someone who breaks into computers. Among programmers it means a good programmer. But the two meanings are connected. To programmers, “hacker” connotes mastery in the most literal sense: someone who can make a computer do what he wants—whether the computer wants to or not.

Paul Graham is :
Paul Graham is an essayist, programmer, and investor. In 1995 he developed with Robert Morris the first web-based application, Viaweb, which was acquired by Yahoo in 1998. In 2002 he described a simple statistical spam filter that inspired a new generation of filters. In 2005 he was one of the founders of Y Combinator. He and Robert Morris are currently working on a new Lisp dialect called Arc

Paul is the author of On Lisp (Prentice Hall, 1993), ANSI Common Lisp (Prentice Hall, 1995), and Hackers & Painters (O’Reilly, 2004). He has an AB from Cornell and a PhD in Computer Science from Harvard, and studied painting at RISD and the Accademia di Belle Arti in Florence.