Summarizing the wealth of recent research on sentence combining as an effective method of teaching students to tighten and vary their written sentences, this booklet explains how and why sentence combining works. The first half of the booklet provides background information on sentence combining, exploring the basis for the claim that sentence combining enhances sentence writing by drawing on built-in linguistic competence, and arguing for a much broader definition of sentence combining. This section also discusses seven instructional issues concerning the use of sentence combining, and lists ten assumptions that seem to underlie the sentence combining approach. The second half of the booklet outlines many ways to use sentence combining in the writing class. This section first deals with cued sentence combining, of the kind popularized by F. O'Hare, then shows how open exercises might be introduced and used in a middle school classroom. It also deals with such practical matters as orchestrating in-class projects, handling "mistakes," and creating various types of sentence combining. The focus then shifts to a variation of pattern practice that may help special students, topics such as grammar, usage/mechanics, and sentence economy. Finally the section moves into arenas more explicitly rhetorical--style, recombining, and generative exercises, the problem of context, and analytic activities of different kinds. (HTH)