 This study will examine the safety and immune response of healthy adult volunteers to AMA1-C1, an experimental malaria vaccine developed by the NIAID. Malaria affects about 300 million to 500 million people worldwide each year, causing from 2 million to 3 million deaths. Increasing drug resistance to the malaria parasite, as well as widespread resistance of mosquitoes the insects that transmit the parasite to pesticides are reducing the ability to control malaria through these strategies. A vaccine that could reduce illness and death from malaria would be a valuable new resource in the fight against this disease. Early tests of AMA1-C1 in 66 people in the United States and in Mali, West Africa, found no serious side effects of the vaccine. This study will test a shorter schedule of vaccinations with AMA1-C1 than that used in the previous studies. 