From publisher blurb:
An Epic World of Adventure Awaits!
Drawing a line through all of our various time periods stands the heroes of the Brotherhood of William St. John. This adventuring society dedicated to exploration, knowledge, and protecting humankind from the forces of evil has existed since the Victorian era and continues into the far distant future. The Brotherhood of William St. John sourcebook is intended to provide a thru-line for your Amazing Adventures 5e games, providing an adventuring society with a deep history and legacy to which your heroes can belong.
Not so much a campaign setting as a collection of options that can enhance just about any setting, the Brotherhood of William St. John is a must-have for any RPG campaign from the 1800s to the sci-fi worlds of thousands of years in the future, with secret societies, organizations, and mysterious places that populate the world, as well as statistics for important members of the Brotherhood and their enemies and allies in each era covered. Using the Amazing Adventures 5e stats, it's widely applicable to just about any game using the Fifth Edition rules!