The sudden and unexpected death of John Paul I in the papal apartments on the evening of September 28, 1978 — after a pontificate of a little more than a month — has given rise over the decades to myriad suspicions, assumptions, and conspiracy theories.

After so many unsubstantiated claims and unconfirmed rumors, we now know what happened in the last hours of the life of “the smiling pope.” Finally, here is an accurate account, backed by in-depth research and previously unpublished documentation, revealed by Stefania Falasca, the vice-postulator for John Paul I’s cause of canonization, in The September Pope: The Final Days of John Paul I.

This compelling story — completely anchored in the facts, including medical reports, first-person testimonies, and archival investigations — is clear and accessible, and exposes the truth about the seemingly inexhaustible rumors that sprang up around this supposed Vatican secret.