Do our thoughts and claims about the world give us rational access to the way the world really is? Can subjective experience ever provide a basis for grasping objec­tive truth? These perennial philosophical questions reach to the heart of every human endeavor, from education to science to everyday, successful practice. Despite the intuitive and nearly universal appeal of realism, influential thinkers from many fields—including educational theory, psychology, cybernetics, literary criticism, biology, and physics—have long followed the skeptics in denying knowers any kind of reliable bridge to the world. This slim volume offers the first comprehensive assessment and critique of radical constructivism, a famously skeptical theory of knowledge with a large following across the academic disciplines. Employing a dialogic mode of discourse, the authors have crafted a remarkably accessible treatise that both details the solipsistic perils of antirealism and defends an alternative, constructivist realist account of our place as knowers in the larger, constraining world.