Rynne is the only writer who has covered every session of 'the greatest religious event in the twentieth century' fully and comprehensively. No one but Rynne reported in detail the debates and struggled of the First Session, which was held in secrecy, and as a result the Council authorities decided to open up to the world press. Now he has completed a major work of history with The Fourth Session, This account of the concluding session of Vatican II shows that the role of Pope Paul VI was decisive.