This memoir was written just after the Civil War by Acting Ensign John Grattan, a staff officer in the Union navy who witnessed some of the war's most significant naval operations. As a clerk and aide to the squadron commander, Grattan served on board the flagship of the largest Union naval command, the North Atlantic Blockading Squadron. This ragtag fleet denied the Confederacy vital supplies and provided a menacing presence in Virginia and North Carolina waters.

The flagship flew the blue pennant to signal the presence of the admiral in command of the squadron. Grattan provides fresh details on the intricacies of blockade running, the battles of the ironclads, the ill-starred advance on Richmond by Major General Benjamin F. Butler, and visits to the front line by President Lincoln, including his triumphant tour of Richmond just days before his assassination.

His narrative includes personal observations of key naval and military leaders, such as Admiral David D. Porter, Rear Admiral Samuel Phillips Lee, and Lieutenant Commander William B. Cushing, leader of the legendary attack on the fearsome Rebel ironclad Albemarle, and rescues less-celebrated heroes from obscurity.

Grattan's observations shed light on how Union naval officers and enlisted men spent their leisure time, dealt with the boredom of blockade duty, reacted to both victory and defeat, behaved under the stress of combat, and coped with death.