This book, written by Sir Charles Knowles, details his expedition to Cartagena. Knowles was assigned to the fireship HMS Success and was ordered to examine the approaches to the port of Chagres. Having completed the mission and formulated a plan of attack, Knowles was given command of the bomb vessels, fireships and other small boats, and he duly bombarded the fortress of San Lorenzo, at the mouth of the Chagres River. The town and castle surrendered, and Knowles was appointed Governor of the castle.