Walter Pater's coming-of-age novel is presented whole in this edition, that readers may witness the change in Marius's philosophical and spiritual views.

Marius is a young man living in Rome in the 2nd century AD, a time when the classical traditions of philosophy were in their maturity. The educated man gravitates from one school of philosophy to another, and even enjoys a stint as secretary to the Emperor Marcus Aurelius, himself a stoic philosopher. As his mind encounters successive cerebral challenges and acquires evermore knowledge, Marius grows curious about the emergence of a new religion - Christianity.

The discovery of the Christian creed marks a new phase in Marius' search for sensation and insight, wherein he is amazed by the life and sacrifice of Jesus Christ. The tight-knit community of early Christians, whose beliefs are not permitted in the Roman Empire, makes a striking impression upon the young fellow.

In favorably reviewing this philosophical novel, critics noted the similarities between Marius's progress and that of the author's. When he first published this work, Walter Pater had already grown notorious for renouncing his Christianity. Upon losing his faith and with it any prospect of joining the priesthood, Pater instead embraced the scholarly circles of Oxford University.