Currently in its 98th consecutive year, the Embryology Course of the Marine Biological Laboratory at Woods Hole has played an important role in the lives of many American developmental biologists. The objective of the Course is to train predoctoral and postdoctoral students for research careers in developmental biology In a unique physical and intellectual environment not duplicated In the nation's universities, medical schools or research institutes. The Embryology Course offers a dally series of formal lectures followed by extended discussions, laboratory research experience, technical workshops and informal seminars over a six week period in the summer. The Course is directed toward predoctoral and postdoctoral students who are committed to research careers in the field of development. The Course addresses major current problems in development, then critically explores those problems through discussions and through laboratories in which advanced new techniques are presented. Outstanding students are chosen from an international applicant pool. The teaching faculty are senior scientists in the field. The Course consists of four modules, each of which is about 10 days long. Each module is staffed by an average of three resident instructors and two outside lecturers. The themes of the modules change from year to year as important developments in the field change. The Course introduces students to a large number of terrestrial and marine embryos including nematodes, insects, amphibians, fish, chick, echinoderms, ascidian, gastropod molluscs, and mice. Techniques include current molecular biological techniques, embryonic manipulation, microinjection and micromanipulation, microscopy and computer enhanced imaging technologies, and a number of immunochemical approaches. Students are challenged to formulate and test hypotheses in a well equipped research environment and under the guidance of experienced research faculty and assistants. The Embryology Course occupies a 10,000 sq. ft. modern laboratory suite in the Loeb Building which is the main teaching facility at the Marine Biological Laboratory. The Lab includes faculty and student laboratories, a marine animal room, constant temperature rooms, imaging lab, tissue culture room, microinjection and micromanipulation facilities, and an equipment room with state-of-the-art research equipment. An adjacent seminar room and lecture hall are used by the Course as well. The Marine Biological Laboratory provides support facilities for purchasing and clerical work, radiation maintenance and safety, confocal and electron microscopy, an animal collection facility, and one of the nation's finest biological research libraries.