Half of the population of the world lives in cities of one million or more. If we don't reach and disciple from these masses, our future missionary and pastoral force will be diminished. The book Urban Impact is a trumpet call to muster our forces but also deals with the philosophy and practical principles that make any ministry in the city successful. Brandishing a practical writing style coupled with real life experiences, John Thompson helps the reader understand the problems, burdens, joys, and powerful impact cities have on the rest of society. Helping the city pastor or missionary develop an effective ministry, Thompson elaborates on seven critical principles necessary for an effective urban ministry. Following this discussion the book turns to two of the leading challenges of great cities. The first being how to reach the disenfranchised--those from minority groups, people who have substance abuse problems, and the homeless, to name but a few. The second challenge deals with one of the greatest foundational problems in our cities and in all of society: the plight of the Absent Father. Other chapters address urban discipleship as the most effective approach to promote life transformation, planting churches in the difficult urban environment, and a topic rarely discussed in urban books, raising a family in the city.