This five-day intensive course (taught twice during the summer) combined lectures on mass spectral interpretation, instrument design and operation, ionization techniques, data systems and instrument trouble shooting with a hands-on laboratory in which the students learned to operate mass spectrometers and analyzed a series of unknown samples. The students attending the course came from a mixture of industry and government laboratories (with a small number from academia), ranging in education from the B.A. to the Ph.D level. Four instrument manufacturers, Hewlett Packard, Varian Associates, Perkin-Elmer, and VG, provided tabletop mass spectrometers (six instruments for 30 students in each class) for the duration of the course. The course also included several demonstrations of sector instrument operation in the Facility. The participants were actively involved in daily debriefings of the laboratory sessions which were focused on data interpretation.