The arrival of the Holy Light on Holy Saturday at the Tomb of Jesus Christ is the only miraculous event in human history that takes place every year, on the same day, for over a millennium. This book records the testimony of history for this remarkable event, covering a period of eight centuries, from the 9th to the 16th century.

Forty-two authors from the medieval world, including ten French, five Muslim Arabs, five Byzantine Greeks, four Germans, three Russians, three Muslim Persians, three Icelanders, two English, two Armenians, one Syrian, one Moldavian, one Swiss, and one Italian historian, describe the great miracle of the Christian world: the Holy Light that, like lightning, descends from heaven every Holy Saturday at the Tomb of Jesus Christ, a few hours before His Resurrection celebration.

In addition, the scientific measurements made at the Tomb of Christ on Holy Saturday in 2008 by Russian physicist Dr. Andrei Volkov confirm the descent of the Holy Light and reveal three events that he himself characterizes as "incredible and completely inexplicable".