Selecting reading materials at the appropriate level for each student is an essential component of promoting literacy, and a number of systems for determining text difficulty are now available. This unique, much-needed reference helps teachers choose from a wide array of approaches and implement them effectively. Provided is a thorough, integrative review of recently developed applications such as Lexiles, as well as traditional readability formulas and systems for beginning readers. Detailed vignettes clearly illustrate how teachers have used these tools in real classrooms and provide tips and pointers for success. Rich with charts, tables, and resources, this practical guide includes an appendix on two electronic book matching programs, Accelerated Reader and Reading Counts.