Gradually evolving from the masted steam frigates of the mid-nineteenth century, the first modern cruiser is not easy to define, but for the sake of this book the starting point is taken to be Iris and Mercury of 1875. They were the RN's first steel-built warships; were designed primarily to be steamed rather than sailed; and formed the basis of a line of succeeding cruiser classes.

The story ends with the last armoured cruisers, which were succeeded by the first battlecruisers (originally called armoured cruisers), and with the last Third Class Cruisers (Topaze class), all conceived before 1906. Coverage, therefore, dovetails precisely with Friedman's previous book on British cruisers, although this one also includes the wartime experience of the earlier ships.