T he final chapters of this volume explore the role o f problem -based learn ing (PBL) in fostering self-directed learning. Definitions o f self­ d irected learning, such as those adopted by the authors o f these chap­ ters, are highly sim ilar to what has been term ed self-regulated learn ing in the educational psychology literature (Zim m erm an, 1986, 1989, 1994, 1998), and we will draw on parallels between these two literatures in our response to these im portan t chapters. As an instructional tech­ nique designed to foster g reater self-direction o f learn ing , PBL is distinctive from but overlaps to some degree such techniques as com ­ puter-assisted instruction (Winne & Stockley, 1998), strategy instruction (Graham, Harris, & Troia, 1998; Hofer, Yu, & Pintrich, 1998; Pressley, ElDinary, W harton-M cDonald, & Brown, 1998), academic studying m eth ­ ods (Z im m erm an, Bonner, & Kovach, 1996), m odeling m ethods (Schunk, 1998; Schunk & Zim m erm an, 1997), tu toring (Butler, 1998), and self-m onitoring (Lan, 1998; Z im m erm an & Paulsen, 1995). Like PBL, each o f these instructional techniques involves social as well as p e r­ sonal team ing com ponents. D uring this commentary, we first consider the com ponents o f PBL and their variations, followed by conceptualiza­ tions of self-directed learning processes, findings repo rted in these chapters and their im plications, and finally, unresolved issues and future research directions.