Prereading assessment was first used to predict school readiness and was an assessment of the child's visual and oral vocabulary skills. By the 1970s, readiness assessment had changed from assessment of a child's developmental probability for success or failure in reading to an assessment of the child's skill development in relation to the reading instructional environment. Most current readiness tests reflect this newer concept emphasizing skills related to decoding and to comprehension. Recent criterion-referenced tests reflect the idea of relating assessment to instruction. This has brought about greater emphasis on subscores rather than on total scores. In the future, more research is needed to discover the relation of understanding concepts of "reading,""word," and "letter" to learning to read. An important implication of readiness assessment research is that teachers should choose the most appropriate prereading test for their particular situations and then plan instructional tasks to follow the information gained from the tests. (TJ)