This book provides a detailed look at the constitutional, historical, and political arguments concerning presidential immunity from prosecution, as well as the opinions of the Office of Legal Counsel that provided the justification for the decision not to prosecute President Trump. Focusing on those opinions, the book examines the constitutional basis of presidential immunity, both textual and historical, as reflected in the deliberations of the 1787 Convention and the ratification debates. The opinions are viewed in the context of the criminal investigations of Presidents Nixon and Clinton that gave rise to those opinions, as well as the pronouncements of the Supreme Court concerning their claims, and those of President Trump to immunity from judicial inquiry. Lastly, the book analyzes presidential immunity in light of the separation of powers, the availability of impeachment, and the discordance between presidential immunity and the rule of law.