This manual has grown out of the authors' experiences in introducing Medical Laboratory Technology, (MLT) students to microbiology and its applications to the clinical laboratory. It is designed to be more than a set of directions for performing and interpreting tests; it integrates theory with the actual peformance of a test, which is why the chapters are called learning units. In addition to objectives for each exercise, relevant background material, and the descriptions needed for interpreting results, this manual includes the following unique features: the format is partly self-instructional; timetables are provided to allow students to organize their work; the material is arranged in a sequence that reinforces educational objectives; the use of organisms that are potentially dangerous pathogens is minimized; and media, reagents, and cultures are selected to put the smallest possible burden on institutions with limited facilities for laboratory preparations.