The subject of rocket development with liquid propellents between 1930 and 1942 is covered as a brief technical overview by Walter Riedel. Based in Germany, Riedel was involved from the late 1920's in developing rockets, initially for a rocket-powered car. He went on to become part of the rocket team working on the infamous V2 vengeance weapon of World War Two at Peenemunde on the coast of Northern Germany. After WW2 he was recruited to the British rocket research team and from 1947 was based at the Rocket Establishment at Westcott, near Aylesbury along with several other German rocket scientists. He wrote this review in 1950, the same year he travelled to the USA where he met up with his former colleague Werner von Braun who had been recruited by the American rocket programme and who would later be a fundamental part of the NASA moon missions. Riedel became a British citizen in 1957 and died at the age of 66 in 1968. Translated from the original German by Dr JC Kelly.