This book provides a very good survey of the seven battlecruisers built for the German navy before and during the First World War. Each of the four designs is examined in some detail, with good clear diagrams to illustrate their main features. The design history starts with the political and military decisions made before work even began on the physical design of the ships. This means that we learn why the German ships were built the way they were, debunking some of the more widely believed myths about their design.
We then get a service history for each of the seven battlecruisers, starting with an explanation of each of their names (rather disappointingly the Derfflinger turns out to be have been named after General Reichsfreiherr von Derfflinger), followed by a list of their captains, then a look at their pre-war and wartime history.
One (at least to me) quite amusing feature of this book demonstrates a tendency amongst historians to adopt the tone of the documents they are working with. The author here has translated a large number of contemporary German documents, and as a result the battle of Jutland becomes the Skagerrak Battle while the fleet sorties of British accounts become fleet advances. On a more serious note, German time was one hour ahead of GMT, and so the times given for the events of battles like Jutland don't match those normally given in English language books.
This level of involvement in the documents is actually one of this book's great strengths. Staff used the terminology that was in use within the German navy during the war. The battlecruisers themselves are referred to as Großen Kreuzer, or "large cruisers", not battlecruisers, a word that did not come into use in Germany until after the war.