The applicability of phonics generalizations, particularly the rule "When two vowels go walking the first one does the talking and the second one is silent," is examined in this paper. The first section reports on a study of the applicability of the two vowel rule to words in first- and second-grade basal readers and on a core vocabulary list; the words studied were those with vowel combinations involving the vowels a, e, i, o, and u. The findings presented indicate that the rule was applicable only 41% of the time. The second section reviews previous research that also indicated the limited applicability of the two vowel rule, as well as research on such topics as teachers' knowledge of phonics generalizations, the usefulness of other generalizations, methods of teaching about phonics, and the relationship of phonics knowledge to reading achievement. Appendixes list the 958 words with consecutive vowels found in first-grade and in second-grade basal readers, divided according to whether or not the two vowel rule proved applicable to them. (GW)