Twenty years after the introduction of the theory, we revisit what it does—and doesn’t—explain. by Clayton M. Christensen, Michael E. Raynor and Rory McDonald Please enjoy this HBR Classic. Clayton M.

Alexandra Twin has 15+ years of experience as an editor and writer, covering financial news for public and private companies. What Is There Ain't No Such Thing As a Free Lunch (TANSTAAFL)? "There ...