William Brian Arthur (born 31 July 1945) is a Belfast-born economist credited with developing the modern approach to increasing returns.

He has been on the external faculty at the Santa Fe Institute, and a Visiting Researcher at the Intelligent Systems Lab[2] at PARC.

Arthur received his PhD in Operations Research (1973) and an M. A. in Economics (1973) from the University of California, Berkeley.

At age 37, Arthur was the youngest endowed chair holder at Stanford University.

Arthur's long association with the Institute started in 1987 with the introduction and support of Stanford economist and winner of the Nobel Prize in Economics, Kenneth Arrow, and Philip Warren Anderson, winner of the Nobel Prize in Physics.

Arthur was named as the first director of the interdisciplinary Economics Program at the Institute beginning in 1988.

Arthur was awarded an honorary Doctor of Economic Sciences degree from the National University of Ireland (2000), and an Honorary Doctor of Science Degree (Honoris Causa) from Lancaster University on 9 December 2009.

Arthur and several other Santa Fe Institute researchers are profiled extensively in the book Complexity by M. Mitchell Waldrop.

Source: The Inner Path to Knowledge Creation, by Joseph Jaworski, contains the story of the U-Process and W. Brian Arthur's contribution to its discovery, based on "Coming From Your Inner Self", reference above.