In this article, findings from case study research of two effective literacy teachers are presented in order to describe in rich detail the nature of effective scaffolding. The teachers worked one-to-one with first-grade students who were experiencing extreme difficulty in learning to read. The complexity of scaffolding is described in terms of the instructional decisions that teachers must make on a moment-by-moment basis about the kind of help (what to work on) and level or amount of help to provide at points of difficulty during reading.