Left ventricular non-compaction is an increasingly recognized familial cardiomyopathy characterized morphologically by deep myocardial trabeculations and a highly variable, but potentially aggressive clinical course leading to cardiac death or cardiac transplantation. Great controversy exists regarding the pathophysiology, diagnostic approach, clinical characteristics, and management of the condition. To date, there are no universally accepted precise diagnostic criteria or management guidelines. Recent clinical studies and basic science research have significantly added to our understanding of LVNC in all of these aspects. This article reviews the literature to date on LVNC and addresses current controversies surrounding the pathophysiology, diagnosis, clinical features, and management.