Value-based health care is no longer merely an aspirational goal or an academic conceptto be defined and debated. It is happening now, and evidence shows that it is working:driving improved outcomes for patients and reducing costs. The stories, articles, andcase studies in the pages that follow attest this new reality, providing rich examplesof individuals and institutions around the world that are leading the way. The cases inthese pages show that outcomes measurement is needed (the "why"), feasible (the"how"), and that, once available, outcomes data have huge potential to improve care andcurb costs (the "what").