The Lyons Mail mystery presents a complex historical crime problem with enduring intrigue. Charles Oman, an established historian, delves into the intricate details of this case, which involves significant historical figures and political machinations of the late 18th century. The narrative examines the events surrounding the lost money intended for General Bonaparte's Italian campaign, weaving together the actions of government directors, notable socialites, and even prominent epicures of the era. The book reconstructs the tangled web of facts and speculation that surround this notorious crime.

The book's focus on a historically significant and complex crime suggests it is a detailed and analytical work. The inclusion of numerous historical figures indicates a deep dive into the social and political landscape of the period. The premise points to a narrative that aims to unravel a notorious mystery through rigorous historical investigation. This approach likely appeals to readers interested in true crime, historical mysteries, and the intricacies of late 18th-century French history.