While the basics of design, conduct, and analysis of clinical trials remain the same, there have been significant changes since the first edition of Clinical Trials was published two decades ago. In this new edition, the author discusses the refinements and improvements made to methods and procedures, changes in the policies and guidelines underlying trials, as well as requirements for registration of trials. He also discusses current practices for data sharing, for gender representation, for treatment effects monitoring, and for ethical standards of clinical trials. The importance of the randomized controlled trial has grown significantly over time and they are now the cornerstone of all evidence-based medicine. Still rich in tables, checklists, charts, and other resources for the trialist, the second edition of Clinical Trials is an indispensable reference for clinicians, biostaticians, epidemiologists, and anyone involved in the design and implementation of a clinical trial.