Inspired by medieval legends about the poet Vergil, who was revered not only as the author of the Aeneid but also as a powerful necromancer, Davidson embarked on his Vergil Magus series in the '60s with the intriguing novel The Phoenix and the Mirror.

In this sequel, Vergil answers a magical summons from Averno, both the wealthiest and the filthiest of cities. The magnates there are worried about the waning and shifting of the natural fires that have fueled their industries and fouled their air.