School reformers hope that converting comprehensive high schools into collections of small schools will produce results similar to those realized in freestanding small schools. Three themes--personalization, professional community, and shared decision making--exemplify the early successes in conversions. But the challenge of sustaining these gains reveals a host of complications that were not anticipated by funders or early adopters of the reform. In particular, the arrangement of a "multiplex" high school can generate tensions between operating autonomous (or, more frequently, interrelated) small schools and maintaining many of the traditions and structures of the comprehensive high school. Examples of supports and inhibitors to small schools reform are highlighted. (Contains 1 footnote.)