This lively, first-hand narrative of the turning-point in the affairs of the Council of Basle was written by Aeneas Sylvius (later Pope Pius II) during his unregenerate conciliar period. It provides us with an important contemporary account of the personalities and principles involved in the election of the anti-pope Felix V. Originally published in 1967, this volume offers the first critical edition and English translation of this work. Unavailable in recent years, it has now been revised by Denys Hay.