British battlecruisers were not a ""failed design"" as is so often claimed, but a very successful and revolutionary one that was critical to, and instrumental in, Britain winning the naval war of 1914-18. This book contains previously untapped evidence from the wrecks of the sunken battlecruisers and detailed analysis of admiralty records to show why Admiral Fisher's famous battlecruiser concept was a revolution that drew together technological breakthroughs, global communications and intelligence gathering to create the first worldwide rapid-response task force.