DFDS 1866-1991 is a comprehensive historical and technical book celebrating the 125-year history of the Danish shipping company DFDS Seaways, from its founding in 1866 through 1991. The book is chronologically organised, beginning with the earliest paddle steamers and progressing through the evolution of ferry and cargo ship design, up to the modern roll-on/roll-off vessels in service at the end of the 20th century. This structure allows readers to see how the company adapted to changing maritime technology and economic conditions over more than a century. The core of the book lies in its detailed narrative and visual documentation: it combines historical text with numerous photographs, technical specifications, and ship profiles that illustrate the development of DFDS’s fleet. Each major class of vessel is featured, with insights into engineering choices, routes, and operational history. Maps, diagrams, and images of tugs, ferries and freighters help bring the history to life and show the tangible results of technological evolution in maritime transport. The volume functions both as a reference work for maritime historians and enthusiasts and as a commemorative publication for the company’s anniversary. Readers interested in shipping, naval architecture, business history or industrial heritage will find it rich in factual detail and visual context. Its combination of narrative overview and technical depth gives a rounded sense of how DFDS grew from a 19th-century enterprise into a major player in 20th-century seafaring.