Organized into three categories of learning environments--computer-based microworlds, classroom-based learning environments, and open, virtual learning environments--the case studies presented in this text apply constructivist theory to practice. While it seems that there are as many interpretations of the theory as there are projects, these case studies do highlight the extent to which creative design can foster constuction of knowledge in rich learning environments. Riesbeck says in chapter five that constructivism "is not a particular model of learning...It does not describe a process or set of mechanisms by which this construction occurs" (49). This explanation seems to account for the variety and differences between case studies. Each study seems to have developed its own model for learning, drawing from theories and research in cognition and instruction. While each theoretical framework reflects some notion of constructivist values, particularly Lebow's set of "seven core values" cited in two of the studies (collaboration, personal autonomy, generativity, reflectivity, active engagement, personal relevance, and pluralism), most seem to emphasize different constructivist principles. It seems that constructivist learning environments share only the broadest of similarities: All are places designed to engage students into constructing knowledge meaningfully. Beyond that, which cognitive principles are to be emphasized and how to make knowledge meaningful seems to be matters left to the instructional designers. Ultimately, Wilson points out, this text serves as a conversation about those issues.

The six computer microworlds all rely on different cognitive models for constructing knowledge--from defined pedagogical goals to processes of interpretation to coached learning by doing to cased based learning. But perhaps the most important aspect of this text is the conversations about making knowledge meaningful. For instance, Dunlap and Grabinger's article on Rich Environments for Active Learning (REALs) argues, essentially, for adopting the REAL approach in traditional higher ed classrooms--extending students' responsibility, promoting meaningful learning, and engaging students in dynamic knowledge construction activities. They offer strategies for implementing thes goals. One of the best chapters in the book, written by Jonassen, Myers and McKillop, also makes an argument for making knowledge meaningful. In this case, using cognitive processing research, the authors call for constructing hypermedia in the classroom rather than relying on this cognitive artifact merely as an information source. Savery and Duffy's chapter on Problem Based Learning is another example. They identify eight instructional principles that can guide teaching and instructional design in a variety of learning environments; PBL is an excellent example. Finally, I should mention Chris Dede's chapter that outlines a number of experiments with artificial realities--SimNet, LucasFilsm's Habitat, Synthetic environments, MUDs and MUSES--exploring the potential of constructivist learning in these environments. This point is, this text is not merely a compilation of case studies, but a conversation about which cognitive processes to emphasize in constructivist learning environments, and how to make knowledge meaningful.

The best teachers create classrooms that are student-centered and instructor-facilitated (rather than directed), allow students to collaborate on authentic tasks, and provide for student ownership. Students are actively engaged, and these teachers model and teach metacognitive processes. I have spent my career as a teacher working to create just such a classroom. Such ideals are also very difficult to realize. Individual teachers face fierce obstacles: established curriculum we must "get through," rigid schedules that work against creative, collaborative environments, members of the community who hold such principles suspect, and lack of rich information sources are just a few examples. This book provides a wealth of ideas for designing constructivist learning environments, but even more importantly, it offers a conversation about the relevance of constructivist principles in light of research in cognition. Teachers must share that conversation as we move into the 21st century.