In this paper we assert that the hierarchical view of data will continue to be popular for a broad class of applications and users. In particular, some of these applications require complex data manipulation which, heretofore, has been dealt with procedurally. In this light, a nonprocedural language, CONVERT, is proposed as a high-level DBMS interface. CONVERT is meant to provide users with a tool for performing complex data manipulation and query of hierarchical data abstractions, called “Forms”. Included in the paper are a description of the Form data abstraction and the CONVERT language, as well as a complete illustrative sample application. © 1976, ACM. All rights reserved.