The Powder Magazine at the Benicia Arsenal by H. Allan Gandy, is intended for historians, museum visitors, military enthusiasts, architects, teachers, and students. It is a presentation about the history, design, construction, builders, and preservation of the Powder Magazine, built in 1857. Many of the interesting facts are summarized from the Army Benicia Arsenal log from the 1850s, not previously researched in detail. There is no other book covering this subject.

The Powder Magazine is unique because of its design and materials. Local sandstone was used to construct four-foot-thick walls. Beautiful, vaulted ceilings and carved capitals on the pillars reflect the stone mason's skill and creativity.

The building of the Powder Magazine in 1857 is presented in detail-from the quarrying of the sandstone and laying of the foundation and walls, to the installation of its beautiful interior columns and arches.