The Preschool Interest Inventory (PSII) has been developed to meet the need for an informal measure of the interests, play behaviors, and communication skills of young children between the ages of 2 and 6 years, particularly those exhibiting delays in language development. The first step in the Inventory process is the Caregiver Interview. In the second step, two 10-minute observations of the child interacting in a freeplay setting are recorded with emphasis on levels and types of play, peer and adult interactions, attending skills, and communication abilities. Individual interests and possible reinforcers are identified for future use in teaching situations. Attending skills are observed with emphasis on eye contact, duration of on-task behavior, and activity level. Additional structured, teacher-directed observations of the child in an individual one-on-one situation and in a small group setting are recommended to gain data on how structure and the intervention of staff affect various dimensions of children's behavior. For use in observations, specific items related to play levels are provided in a suggested list of common preschool play materials and activities. The concluding step, writing a narrative summary, results in a general impression and an interpretation of the child's preferences and behaviors in a variety of play settings, which should prove useful in formulating instructional program objectives. (RH)