A study was conducted to determine the precise content of elementary school spelling instruction. Spelling textbooks for grades one through six from seven major commercial publishers were selected on the basis of their use in elementary classrooms and were subjected to a critical, computer-assisted analysis in order to identify and classify the specific spelling skills actually taught through textbook instruction. The most striking fact to emerge from the investigation was that there is very little agreement among the series as to the appropriate content of spelling books. The results provide a better understanding of current spelling instruction as well as data for the construction of instruction-referenced assessment instruments such as the Southwest Regional Laboratory's Proficiency Verification Systems (PVS). PVS is an assessment inventory that matches assessment to actual instruction, and this investigation was directly related to the development of spelling inventories similar to the PVS inventories that have already been developed and implemented in mathematics and reading. (Appendixes identify the seven spelling series studied, the distribution of skills in the seven series, and suggested levels for assessing spelling content.) (AEA)