The Cold Spring Harbor Laboratory proposes to continue its highly successful summer course in Advanced Bacterial Genetics. This course has its roots in the original Cold Spring Harbor Bacteriophage Course initiated by Dr. Max Delbruck in 1945. The course will be offered for three weeks in June from 1993-1997. This course prepares the participant to enter directly into research that makes use of advanced and/or specialized techniques and concepts in molecular genetics. Participants gain extensive first-hand experience with materials and systems that have led to recent advances in prokaryotic molecular genetics. A solid grounding in classical genetic analysis supports training in contemporary uses of transposon mutagenesis, operon and gene fusion technology, molecular cloning, site-specific mutagenesis and polymerase chain reaction as applied to diverse problems in bacterial and bacteriophage genetics. This course, which is unique in providing instruction in both genetics and molecular biology, gives participants the wherewithal required to perform analogous experiments in their home laboratories. The course instructors are chosen on the basis of their contributions to and knowledge of the field of bacterial genetics. Daily discussion periods cover the basis of the methodology used and fine points of experimental design and analysis. The course instructors invite guest lecturers to give up-to-the-minute reports on current research. The lecturers have all made significant contributions to their fields, so that direct contact with the lecturers is a valuable experience, especially for the younger course participants. Because the Laboratory is open at all hours, and because of the informal atmosphere, spontaneous discussions between participants, instructors, lecturers and laboratory staff are constant occurrences. Course participants range from graduate students to senior investigators. They are chosen by the course instructors from a pool of highly-qualified and deserving applicants. Because of the short duration of the course, senior scientists can easily attend to experience a period of intense training in an environment that is remote from other demands on their time and attention.