U.S. Center for World Mission
The United States Center for World Mission (USCWM) is a center located on 35 acre campus in Pasadena, California where various missiologists, practitioners, and groups work together to strategize, research and promote ideas that will help to complete the unfinished task of reaching every people group with the Gospel. The campus is run by members of the Frontier Mission Fellowship. The US Center has been described as a frontier missions think tank or “missions Pentagon.” Many ministries had their genesis at the Center or have been resident for a season before moving on to new locations.
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.
Dr. Winter was named among the top 25 Most Influential Evangelicals in America by TIME magazine. 
He was a strong influence on Pastor Rick Warren Warren who learned from Winter that a church should not be judged by how many people it seats, but rather by how many people it sends to mission fields. Basing his church on that model, Warren said his church has now sent thousands of people to some 100 nations, and is first church to send people to every country in the world.
Pastor John Piper is quoted as saying, "Nobody in the area of missions had a greater impact on me. Ralph Winter was probably the most creative thinker I have ever known. I mean, on any topic that you brought up, he would come at it in a way you have never dreamed of. He saw all things in relationship to other things that you would never think of relating them to."
Pastor Jack Hayford said of Winter, "I have never known a more diligent servant of the gospel; one so marvelously wrapped in the giftpackaging of a profound scholar, missionary, pioneer thinker and friend." 
The famous evangelist, Rev. Billy Graham said, "Ralph Winter was a man of God who gave a vision to many Christians of a world in need of the gospel. I used to meet with him on many occasions, often in small group prayer. Some of my vision for world evangelization came from my interaction with him, and I am grateful.
The US Center, and its affiliated ministries, is run by members of the Frontier Mission Fellowship (FMF) which was founded by Dr. Winter.
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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, including Pastor John Piper, 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.
Before the U.S. Center for World Mission was established, God was moving in the hearts of Ralph and Roberta Winter. While teaching other missionaries, the Winters gained keen insight into the task of world evangelization. They realized that even if every Christian in the world witnessed to everyone in his or her own culture, only half of the world's population would hear the gospel. Because of barriers of culture and language, the rest of the world was sealed off from the Gospel in people groups without a viable, indigenous, evangelizing church.
To establish a church among every Unreached People group is the driving vision and burden of the U.S. Center for World Mission. As the Center was getting started, many other ministries were formed along the way.
Even before the Center began, the need to make mission resources more available led to the founding of the William Carey Library Publishers. Because of WCL, valuable mission books and videos are published and distributed no matter what the quantity.
In 1974, the Institute of International Studies arose out of a need not only to train people as missionaries but also to provide an intensive foundation on what is happening in the world and what needs to happen. Now called the "Perspectives on the World Christian Movement", or "Perspectives" for short. With over 100,000 alumni globally, the course covers information crucial to any person interested in God's global purposes and has said to be a life changing experience for many who have taken it.
Building on these ministries, the Winters took the radical step by founding the U.S. Center for World Mission in 1976 in a few rented offices on the 35-acre campus of Pasadena Nazarene College. Their purpose was to pull people together to concentrate on the plight of the Unreached Peoples. To most effectively fulfill this purpose the U.S. Center went on to purchase the campus which was up for sale at that time. They had little financial backing but a great dream of a unique, missionary center. The money came in miraculous ways, primarily through small gifts of individual Christians around the country. The final payment for the campus was made in 1988.
Harassed for eleven years by huge property payments, the U.S. Center for World Mission nevertheless concentrated on spreading the vision for the unreached. The financial struggles themselves became a soapbox from which to proclaim the vision. The Center hoped to motivate thousands who could then build a movement that would bring tens of thousands in touch with God's heart for the unreached. The teamwork and prayer of the staff and thousands around the country helped to thrust this movement forward, building a network that is yet to be fully utilized.
The efforts to establish the U.S. Center have also led to the development of a wide-ranging movement to the frontiers of mission that now involves thousands of people and hundreds of missions organizations. The U.S. Center now seeks to serve this growing movement with resources, information, and strategic insights that can help the movement grow and effectively reach all the unreached peoples. 
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 0-87808-448-7.
- Ralph Winter - The 25 Most Influential Evangelicals in America - TIME
- Thousands Celebrate Ralph D. Winter's Life, Impact
- John Piper’s Personal Tribute to the Late Ralph Winter - Desiring God
- Preachers, Pastors Pay Tribute to Dr. Ralph D. Winter
- Mission Network News
- Dave Datema Named to Succeed Dr. Ralph Winter « UBCentral
- Interview: New General Director of Frontier Mission Fellowship
- Perspectives on the World Christian Movement
- "What is the U.S. Center for World Mission?". U.S. Center for World Mission. Retrieved 2009-06-27.
- "William Carey Library web site". William Carey Library. Retrieved 2009-06-27.
- "Perspectives web site". U.S. Center for World Mission. Retrieved 2009-06-27.
- "INSIGHT web site". U.S. Center for World Mission. 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
-  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