* "The Titanic and Other Ships that Vanished at Sea" (1988): This book explores the history of shipwrecks and maritime disasters, including the sinking of the Titanic. It's a fascinating and insightful look at the dangers of the sea.
* "The Greatest Treasure Hunt in History" (1992): This book tells the story of the search for the lost treasure of the Portuguese galleon "Flor do Mar," which sank off the coast of South Africa in 1552. It's a gripping tale of adventure and discovery.
* "The New History of the Titanic" (2012): This book offers a comprehensive and updated account of the Titanic tragedy, incorporating new research and perspectives. It's considered a definitive work on the subject.
* "A History of the Atlantic Ocean" (2017): This book is a sweeping and ambitious account of the history of the Atlantic Ocean, covering its geological formation, its role in human history, and its environmental challenges. It's a landmark work that sheds new light on the importance of this vast body of water.
Besides these books, Ryan has also published numerous articles and essays on maritime history. He is considered a leading expert on the history of the Atlantic Ocean and its relationship to human civilization.