This is the untold story of Isaac Lubbock (1891-1961), an unsung hero, who during World War II was the only scientist working at the cutting edge of both jet propulsion and liquid fuel rocketry, two world-changing technologies. In 1940 he invented the combustion chamber for Frank Whittle's jet, without which it couldn't fly. Whittle later said, 'All subsequent engines stems from Mr. Lubbock's work'. This remains true. In 1942 he invented the first British liquid fuel rocket. This enabled him to convince Churchill that the V2 threat was real, in the face of acrimonious scorn from the scientific establishment including Lord Cherwell, Churchill's scientific adviser. He received no public recognition. This book aims to rectify the injustice done to one of the great British inventors and engineers.