(written from a Production point of view)
The Brandeis-Bardin Institute, now called the Brandeis-Bardin Campus at American Jewish University, is a religious retreat in the hills above Simi Valley in Southern California. Satellite imagery of The House of the Book is available here
The distinctive and futuristic architecture of their "House of the Book" building has been used several times in Star Trek productions, usually modified with a matte painting. It first appeared as Camp Khitomer in Star Trek VI: The Undiscovered Country, although the foreground walkway and fountains were shot by Industrial Light & Magic at the Fireman's Fund Building in Novato, Northern California. It later appeared as Lore's Borg compound in the Star Trek: The Next Generation sixth and seventh season episodes "Descent" and "Descent, Part II" in 1993.