This unique book, based on full access to official records, exposes for the very first time the mysterious life and career of Desmond Morton, intelligence officer and personal adviser to Winston Churchill during the Second World War. After distinguished service as artillery officer and aide-de-camp to General Haig during the First World War, Morton worked for the Secret Intelligence Service (SIS) from 1919 to 1934, and was involved in secret operations against Bolshevik Russia and a resurgent Germany. Morton met Churchill on the Western Front in 1916, supporting him throughout the 'wilderness years' and moved to Downing Street as the Prime Minister's intelligence adviser in May 1940. There, he remained in a liaison role until the end of the war, when he became a 'trouble shooter' for the Treasury in a series of tricky international assignments. Throughout Morton's career, myth, rumour and deliberate obfuscation have created a misleading picture of his role and influence. The story of this 'man of mystery' shines a light into many hitherto shadowy corners of British political history in the first half of the twentieth century. This book will be of interest to scholars and general readers with an interest in the Second World War, intelligence studies and the career of Winston Churchill.