Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. In computing, a hacker is a person in one of several distinct (but not completely disjoint) communities and subcultures: People committed to circumvention of computer security. This primarily concerns unauthorized remote computer break-ins via a communication networks such as the Internet (Black hats), but also includes those who debug or fix security problems (White hats), and the morally ambiguous Grey hats. See "Hacker (computer security)". A community of enthusiast computer programmers and systems designers, originated in the 1960s around the Massachusetts Institute of Technology (MIT)'s Tech Model Railroad Club (TMRC) and MIT Artificial Intelligence Laboratory. This community is notable for launching the free software movement. The World Wide Web and the Internet itself are also hacker artifacts. The Request for Comments RFC 1392 amplifies this meaning as "[a] person who delights in having an intimate understanding of the internal workings of a system, computers and computer networks in particular." See "Hacker (programmer subculture)".