Thoroughly updated and revised, the new edition of this accessible guide aims to outline why there is a gap between research findings and what actually happens in clinical practice. It covers a number of topics including the sources of information on clinical effectiveness and methods of information, how to close the gap between research and pratice, potential roles for lay people, the role of decision support, barriers to the use of evidence in clinical practice, the role of decision analysis, implementing research findings in developing countries and how to encourage the implementation of results from economic evaluation.