This article systematically reviews research on the achievement outcomes of four types of approaches to improving the beginning reading success of children in kindergarten and first grade: Reading curricula, instructional technology, instructional process programs, and combinations of curricula and instructional process. Study inclusion criteria included use of randomized or matched control groups, a study duration of at least 12 weeks, valid achievement measures independent of the experimental treatments, and a final assessment at the end of grade 1 or later. A total of 63 studies met these criteria. The review concludes that instructional process programs designed to change daily teaching practices have substantially greater research support than programs that focus on curriculum or technology alone. In particular, positive achievement effects were found for "Success for All, PALS," phonological awareness training, and other programs focused on professional development. (Contains 5 tables.)