Inspired by a hugely successful series entitled Treating Individuals, originally published in The Lancet, this volume will become essential reading for any professional involved with performance and evaluation of trials and systematic reviews or clinical patient care. There are many books explaining the importance of evidence-based medicine and how randomised clinical trials (RCTs) and systematic reviews should be performed. However, this is the first book to tackle the apparent conflict between the importance of evidence-based decision making and the widely-held view that it is often very difficult to apply the overall results of RCTs and systematic reviews to decisions about individual patients in routine clinical practice. The book brings together experienced clinicians, statisticians and trialists to focus on the two key questions that are most frequently asked by clinicians. Is the evidence relevant to my clinical practice? How can I judge whether the probability of benefit from treatment in my current patient is likely to differ substantially from the average probability of benefit reported in the relevant trial or systematic review? These questions are addressed from methodological and clinical perspectives, and potential approaches to improving the targeting of treatment are considered, with detailed reviews of several areas of medicine and surgery where useful progress has been made.