We thank the residents of Asembo and Gem, community leaders, and health facilities staff whose interest, support, and cooperation made this study possible. Community residents, particularly the nyamrerwa (traditional birth attendants), village monitors, and other field staff provided the essential network for collection of the data presented in these papers. Without their hard work, and that of other members of the study team, including laboratory personnel, data entry clerks, clinical officers, drivers, theater group members, network support staff, and administrative support staff, this project could not have succeeded. Many individuals served in key supervisory roles, including Michael Onyango, George Olang, Richard Odhiambo, George Okoth, Helen Nyanjage, Millicent Atieno, Maurice Ombok, Richard Otieno, Caleb Ouma, Polycap Obel, James Kwach, Thomas Ondieki, David Anyona (deceased), Michael Othim, and Jane Oiro. Critical administrative support was provided by Pauline Abdallah, Benta Kamire, Lucy Atieno, Ben Wafula, Austin Otieno, Jeremy Watkins-Pitchford, and Christi Murray. Essential computer support was provided by Tony Ojwang and Winston Olwande. The American Embassy in Nairobi and the Kenya Medical Research Institute (KEMRI) provided essential logistical and administrative support. We thank, in particular, the Director of KEMRI, Dr. Davy Koech, for his many years of support, and the former American Ambassador to Kenya, Ms. Prudence Bushnell, for her interest and enthusiasm, which did not flag even during difficult times. We are very grateful to Dr Aggrey Oloo for his assistance, advice, and support. We appreciate the contributions made by the Ministry of Health, particularly the former Provincial Medical Officer, Nyanza Province, Dr. Richard Muga, and our colleagues from the Malaria Control Programme. We thank Dr. Juliana Otieno for her advice and support. Kevin DeCock, Larry Slutsker, and Rick Steketee provided helpful advice on many early versions of these papers. Remaining errors are, of course, ours. On the other side of the ocean, Sue Binder and Dan Colley of the Division of Parasitic Diseases at the Centers for Disease Control and Prevention were especially supportive. At the United States Agency for International Development (USAID), we thank John Paul Clark, Mary Ettling, Neen Alrutz, Dennis Carroll, Victor Masbayi, and Gary Newton for their support and encouragement. Students from many different institutions, both within and outside of Kenya, participated at different stages of the project; we are grateful for their assistance and hope they benefited from the experience. Major financial support was provided by the USAID, with additional support from the Special Health Fund of the Royal Netherlands Embassy in Nairobi, and the Netherlands Foundation for the Advancement of Tropical Research (WOTRO).