This book shows how Israel Mattuck was probably the most influential figure in the development of the Liberal Jewish Synagogue in the UK and the wider Liberal Jewish movement through his involvement with the World Union for Progressive Judaism, which he chaired from its foundation in 1926 until his death in 1954. His authority was partly the result of his personality and intelligence, but also his thorough Jewish education, which in England only Israel Abrahams could equal, together with his first-hand exposure to the American Reform Movement. At the time of his death, Israel Mattuck was hailed as a 'Jewish Archbishop of Canterbury' and the magnitude of his achievements is undeniable: he led the LJS and the Liberal Jewish movement through two world wars, he produced prayer books that provided the liturgy for the Liberal Jewish movement for over 40 years, and he was one of the prime instigators in setting up the London Society of Jews and Christians, which he co-chaired for many years and which provided the model for the foundation of the Council of Christians and Jews in 1942.