There are at least two kinds of phonetic knowledge: phoneme synthesis and analytic knowledge. In phoneme synthesis a person demonstrates phonetic knowledge by being able to assemble segments into larger units. With analytic knowledge one knows that syllables or words are analyzable into constituent segments. One type of knowledge enables learning to read and the other type follows from learning to read. These issues were the background for a longitudinal study carried out with 99 beginning readers. In the study, children were tested at four points throughout the school year. At each point children were tested on three phonetic tasks, a test of simple sentence-reading, and a test of pseudoword reading. The two phonetic tasks of main interest were a test of phoneme synthesis and a test of phoneme deletion. Of central interest was the relationship between the child's reading ability and his or her performance on these tasks. From this study it was concluded that regardless of instructional method, phoneme synthesis ability was necessary for reading to occur, but it was not sufficient. Phoneme deletion was sufficient for reading to occur but not necessary. Thus, the ability of phoneme analysis is one that is followed by early skills in reading, whereas the ability of phoneme synthesis is one that precedes early skills in reading. This suggests that the relationship between phonetic knowledge and early reading is one of mutual facilitation based on the intimate relationship between spoken and written language. (HOD)