This manual was written as an aid to teaching assistants (TAs) who conduct the laboratory portions of life science courses at the University of Washington. In general, this manual does not present specific factual material. Rather, it offers suggestions on how to handle various teaching situations and provides a framework to use in many different life science lab applications. Included in the contents are: "What Is a Laboratory TA?"; "What Can You Teach in the Lab?"; "Interacting with Your Students"; "Interacting with Your Colleagues"; "Integrating the Laboratory with the Lectures"; "Preparing for a Lab"; "Running a Lab"; "Evaluating Student Performance in the Lab"; "Evaluating Your Effectiveness as a T.A."; "Safety"; "Working with Biological Material"; "Care of Equipment";"Designing Your Own Laboratory Exercise"; and "Teaching Resources." The "Ten Essentials of Being a Successful T.A." are listed in the concluding section. (CW)