The first Edition of this book was created in 2005-06 in response to voiced frustrations among junior medicine, cardiology and off-service residents rotating through cardiology as well as non-cardiologist physicians who were overwhelmed by the sheer number of cardiology trials. After repeated requests for references of “just the important trials” or “just the trials that changed practice”, we compiled a user-friendly quick-reference guide of the 25-30 studies that had the biggest impact on clinical practice across the breadth of cardiovascular medicine. With each new addition of the book, we continue to comb through the cardiovascular literature for robust trials that consolidate mature lines of evidence and ultimately persuade us to change practice. The unique feature of the book is its Perspectives section that explains the study and its context. We hope this book will be a useful and relevant companion to you.