Librarium was built on one of the oldest and most well-validated memory techniques in human history: the method of loci, also known as the memory palace. First documented in ancient Greek and Roman rhetorical training, the technique involves mentally placing items to be remembered at specific locations along a familiar imagined route or within a familiar imagined building, then mentally walking through that space to retrieve them. The spatial encoding of information alongside emotional and environmental context significantly improves recall compared to rote repetition.

Librarium's insight was that VR is ideally suited to this technique. Rather than imagining a memory palace, a VR user inhabits one. Flashcard content becomes a three-dimensional object placed at a specific physical location within the virtual library environment. The user walks to it, sees it, answers it, and the physical act of moving through a space and encountering objects at known locations engages the spatial memory systems that the method of loci exploits. Launched in September 2022 in partnership with Kaplan — the leading test preparation company — the app included over 100 curated flashcard decks covering environmental sciences, biology, philosophy, history, and other subjects, plus the option to create custom decks via a companion mobile app.