This document contains a detailed listing of topics covered in the mathematics and reading portions of the 1973 Form S and the 1981 Form U of the Comprehensive Tests of Basic Skills (CTBS). Chages in the overall structure of the CTBS, new topics included in Form U and old topics not covered, and changes in the arrangement of topics across the different test levels are discussed. Form U has more levels than the older Form S; there is not a one-to-one correspondence between test levels in CTBS and grade levels in school. On the reading tests, the most prominent change is a fairly large increase in the number of skill areas and topics that are tested. On the mathematics tests, two patterns are evident: (1) there are more skill areas and more topics covered by the newer test; and (2) the skills are organized differently across the test levels. (Author/BW)