"Mysterious Relics" is a nicely compact reference for the GM to quickly stir up encounters involving temples and sacred artifacts.
The "Pantheon-Specific" in the title refers to the classic Greek mythology, from Aphrodite, Athena, Ares, and Artemis to Zeus himself.
The beginning provides ideas, general hints, and temple-related scenarios for the materials in the book. A major side-bar on Classical Temple Furnishings gives many symbols, animals, and varied objects for both major and minor Olympic deities, and indicates which items are appropriate for more than one deity.
Much of the remainder of the book is given to detailing twelve deity-specific relics of the major Olympians for immediate use. The detailed relics are given in 4th Edition Dungeons & Dragons but could be readily used in other systems or system-agnostic campaigns.
Two more major sidebars provide compact, fast info for the busy GM: a longer selection of Temple Objects and Furnishings including a variety of items of many varied religions without reference to the Greek deities, and a list of Religious Garb and Accouterments (also deity-free) with not only clothing but also bodily modifications (potentially painful ones) for the priests, acolytes, minions, and lackeys.
I can see using this as a go-to reference for a last-minute game-session authoring or a more leisurely campaign creation for a major adventure.