The United States Center for World Mission (USCWM) is a place where mission agencies work together to strategize, research and promote ideas that will help to complete the unfinished task of reaching every people group with the Gospel. It has been described as a missions think tank or “missions Pentagon.”
Ralph D. Winter (1924-2009) and his wife Roberta Winter (1930-2001) served as Presbyterian missionaries to a Mayan tribal group called the Mam people in Guatemala for 10 years. Roberta was a registered nurse who graduated top of her class.
In 1967, Ralph served as professor at the School of World Mission (or SWM, now called School of Intercultural Studies) at Fuller Theological Seminary for 10 years. Among other things, he taught the historical development of the Christian movement. Roberta was very involved in Ralph's teaching.
The USCWM was founded by the Winters in 1976, two years after Ralph presented a paper about hidden (or unreached) people groups at the 1974 Lausanne Congress on World Evangelization. During the presentation, Winter defeated the widely held idea among mission groups at the time that cross-cultural evangelism effort was no longer needed because every political country had heard the Gospel. Using statistics and graphs, and with input from around the world, Winter showed that there were still 2.5 billion people who could not hear the Gospel in their own languages and cultural setting and therefore cross-cultural evangelism is not only needed but urgent.
The presentation became known as a watershed moment for world missions and many believe it changed the global strategies of mission agencies thereafter.
After coming back to the United States from the conference, Winter felt that there needed to be a place where mission agencies can collaborate to complete the unfinished task. At first he tried to persuade Fuller Theological Seminary, where he was a professor, to create such a missions think tank. Fuller decided not to develop such a center so Winter took it upon himself to found the center.
He left his tenured faculty position at Fuller and along with Roberta and a receptionist, and only $100 in cash, began the task of purchasing the former campus of Pasadena Nazarene College to be the site of the USCWM.
The USCWM focuses on advancing God's primary purpose: His glory among all nations. To this end, the Center: studies and promotes global mission efforts for new insights; seeks to recognize what is missing; proposes answers to unresolved problems; and pilots solutions for others to follow or adapt; and mobilizes people to engage in the task.
“We seek to avoid doing what others can or will do, and focus our limited resources on critical contributions to the mission effort that others can’t make or won’t make” -USCWM 
Unreached People Groups
Originally called hidden people groups, mission leaders later agreed to change the name to unreached to better capture the image that the Gospel had yet to reach these people in their own language and culture. An unreached people group is one where there is no viable, indigenous, evangelizing church movement.
In 1976, when the USCWM was founded, there were an estimated 17,000 unreached people groups. The latest figure as of 2009 places the number of unreached people groups at about 7,000, but some of that decrease is from a better understanding of the situation "on the ground" in any given people group.
Major Ministries of the USCWM
William Carey Library (WCL) was founded in 1969 by the entire Winter family while Ralph was at the School of World Mission. It now serves as the Center's media publishing arm. At the request of the faculty of the SWM, Winter created the WCL to ensure that important mission tools, which may not be cost effective for others to publish could still be printed and distributed. The WCL also acts as a clearinghouse for more than 90 different publishers, handling and distributing mission books and resources around the world.
Perspectives  on the World Christian Movement is a college level course offered in 200 locations across the U.S. (and in select places globally) with over 80,000 alumni in the U.S. and Canada. Now a ministry of the U.S. Center for World Mission, it seeks to examine the Biblical, historical, cultural and strategic dimensions of what God is doing around the world. Many students who come out of Perspectives decide to become missionaries, but it is really targeted at those who will mobilize, pray and otherwise promote and support mission in their local churches.
Mission Frontiers Magazine In 1979, the USCWM began to produce a newsprint magazine called Mission Frontiers. It has continued publication since, and it is a conduit for some of the strategies, breakthroughs and current events in the mission world globally.
INSIGHT: Intensive Study of Global History and Theology  A one year college program that walks students through all of history in one year with a biblical and missiological perspective.
- ↑ Winter, Roberta H. (2003). I Will Do a New Thing: The U.S. Center for World Mission -- And Beyond. Pasadena, California, USA: William Carey Library Pub.. ISBN 0-8780-8448-7.
- ↑ "What is the U.S. Center for World Mission?". U.S. Center for World Mission. http://www.uscwm.org/about/mission.html. Retrieved 2009-06-27.
- ↑ "William Carey Library web site". William Carey Library. http://missionbooks.org/williamcareylibrary/home.php. Retrieved 2009-06-27.
- ↑ "Perspectives web site". U.S. Center for World Mission. http://www.perspectives.org/site/pp.aspx?c=eqLLI0OFKrF&b=2806295. Retrieved 2009-06-27.
- ↑ "INSIGHT web site". U.S. Center for World Mission. http://www.yearofinsight.org/. Retrieved 2009-06-27.
- Winter, Roberta H. (2003) I Will Do a New Thing: The U.S. Center for World Mission – And Beyond. Pasadena, California, USA: William Carey Library, 1987.
- Winter, Ralph D. "Frontiers In Mission". Pasadena, California, USA: William Carey Library 2005
- Winter, Ralph D. (1966) "This Seminary Goes to the Student". World Vision Magazine. Monrovia, World Vision, Inc.
- Winter, Ralph D. (1969a) "The Reluctant Missionary". World Vision Magazine. Monrovia, World Vision Inc.
- Winter, Ralph D. (1969b) "The Seminary That Became a Movement". World Vision Magazine. Monrovia, World Vision, Inc.
- Winter, Ralph D. (1970) "The Acron that Exploded". World Vision Magazine. Monrovia, World Vision, Inc.
- Winter, Ralph D. (1972) "The Extension Model in Theological Education: What It Is and What It Can Do". Pasadena, Fuller Theological Seminary.
- Winter, Ralph D. (1992) "Defining the Frontiers: A Response". International Journal for Frontier Missions, 9, 9-11
- Winter, Ralph D. (2003b) "Eleven Frontiers of Perspective (Part 2)". International Journal for Frontier Missions, 20, 135-144
- Winter, Ralph D. and Hawthorne, Stephen C. (2009) "Perspectives on the World Christian Movement: a Reader". Pasadena, William Carey Library
- Winter, R. D. and Latourette, K. S. (1970) "The twenty-five unbelievable years, 1945 to 1969". South Pasadena, William Carey Library
- Winter, R. D. and Winter, R. H. (1968) "When School is Half a World Away". World Vision Magazine. Monrovia, World Vision, Inc
- Winter, R. D. (1975) The Highest Priority: Cross-cultural Evangelism. In Douglas, J. D. (Ed.) Let the Earth Hear His Voice. Minneapolis, World Wide Publications
- USCWM official website Official website of the U.S. Center for World Mission
- Dr. Ralph D. Winter Official website of Dr. Ralph D. Winter
-  The Legacy of Ralph Winter
- USCWM's William Carey Library Mission Resource Publishing website
- Perspectives Perspectives on the World Christian Movement website
- Fuller Theological Seminary Official website of Fuller Theological Seminary
- Lausanne Movement for World Evangelization Official website of the Lausanne Movement for World Evangelization
- Mission Frontiers Mission Frontiers website