There are some insightful, thought-provoking, and profound books around that are well worth a read if you're interested in expanding your understanding on a range of topics.
Here are a few we've found helpful or interesting (some are quite textbook-y but worth a look):
About Development
Walking With The Poor: Principles and Practices of Transformational Development, by Bryant Myers (1999)
The Myth of Community: Gender Issues in Participatory Development, edited by Irene Gujit & Meera Kaul Shah (1998)
About Aid
Ending Aid Dependence, Yash Tandon (2008)
Dead Aid: Why Aid Is Not Working and How There Is a Better Way for Africa, by Dambisa Moyo (2009)
The Trouble With Aid: Why Less Could Mean More for Africa, by Jonathan Glennie (2008)
About cross-cultural work
Cross-Cultural Conflict: Building Relationships for Effective Ministry, by Duane Elmer (1993)
Serving with Eyes Wide Open, by David A Livermore (2006)
About Christian responses to poverty
Rich Christians in an Age of Hunger, by Ronald J Sider (1997)
The Sound of World's Colliding, by Krisin Jack (2009)
The Irresistible Revolution, by Shane Claiborne (2006)
Beyond Guilt: Christian Responses to Suffering, by George S Johnson (2000)