Henry Chadwick & Gregory Dix 
Treatise on the Apostolic Tradition of St Hippolytus of Rome, Bishop and Martyr [PDF ebook] 

First Published in 1995. This book first appeared in 1937, and includes the Apostolic Tradition of St Hippolytus which is generally recognised as the single more illuminating single source of evidence on the inner life and religious polity of the early Christian Church. With a revised preface as well as the original first edition preface.