What is the name of the first novel in Gene Wolfe's 'The Book of the New Sun'?

The first novel in Gene Wolfe's The Book of the New Sun is The Shadow of the Torturer. Published in May 1980, it introduces Severian, an apprentice in the Guild of the Seekers for Truth and Penitence, commonly known as the torturers' guild.

Severian lives in the immense, ancient city of Nessus in a far-future Earth where the Sun has dimmed and the planet has grown cold. After showing mercy to a prisoner, he is exiled from the guild and ordered to travel to Thrax, where he is expected to become an executioner. The journey becomes the beginning of a much larger story involving political power, lost technology, memory, and religious symbolism.

The novel is the first of four main volumes. It is followed by The Claw of the Conciliator, The Sword of the Lictor, and The Citadel of the Autarch. Wolfe later added The Urth of the New Sun as a coda.

The title can cause confusion because The Book of the New Sun is often treated as one complete work, but its opening volume is a distinct novel. The other listed choices are later books in the same sequence.