The authors present the results of a 2-year longitudinal study of 228 Norwegian children beginning some 12 months before formal reading instruction began. The relationships between a range of cognitive and linguistic skills (letter knowledge, phoneme manipulation, visual-verbal paired-associate learning, rapid automatized naming (RAN), short-term memory, and verbal and nonverbal ability) were investigated and related to later measures of word recognition in reading. Letter knowledge, phoneme manipulation, and RAN were independent longitudinal predictors of early reading (word recognition) skills in the regular Norwegian orthography. Early reading skills initially appeared well described as a unitary construct that then showed rapid differentiation into correlated subskills (word decoding, orthographic choice, text reading, and nonword reading) that showed very high levels of longitudinal stability. The results are related to current ideas about the cognitive foundations of early reading skills. (Contains 1 figure and 14 tables.)