Heart disease in children has a number of diagnostic traps for the unwary, and all of us involved in the specialty have been caught at one time or another. For example, it is sometimes very difficult to differentiate between respiratory and cardiac disease in infants and between neurological and cardiac conditions in older children, and the consequences of taking the wrong path can be significant. This book is a collection of cases highlighting situations which can ensnare even the best cardiologist. Although they illustrate the importance of taking a good history and performing a thorough examination, the most important lesson is learning to keep an open mind and develop the ability to think laterally. As clinicians we need to have the confidence to make a decision for our patients but also the humility to be able to acknowledge that we don’t always get it right first time, and it is imperative that we learn from the experience. We hope the reader will find these short chapters interesting and while they are not evidence-based medicine in the true sense, they do represent a wide range of clinical experience from which we can all learn.