This edition of Microorganisms: A Laboratory Manual has been enhanced through the addition of clear learning objectives for each laboratory experience. All of the experiments have been student-tested and modified whenever necessary. The last few weeks of the course are devoted to the identification of unknowns, where the student gets an opportunity to use what was learned during the semester. The goals of the course are to prepare students for upper division microbiology and molecular biology courses both here and elsewhere, for careers in medical and cytotechnology, nursing, and clinical microbiology, for curricula in medical, dental and veterinary school and to provide broad, general microbiology training for those students for whom this is their only microbiology course.