This series makes up the bulk of the American Laboratory Theatre collection, consisting of incoming and copies of outgoing correspondence, financial documentation, publicity and informational material about both the school and the theatre, and other related records. The series documents the Lab's efforts to remain financially solvent as well as the day-to-day workings of the school and theatre. The series is further sub-divided into four sub-series for general administrative records, correspondence, financial and legal documentation, and publicity and fundraising.

Oversize materials have been physically separated and are located at MS Q73 and MS Qa20. Volumes are located at MS K33 and MS E278. These materials are described at the end of each relevant subseries. While all materials are described alphabetically by topic or correspondent, materials have for the most part remained in their original groupings.