The Department of Extra-Vulcan Researach was a division within the Vulcan Science Academy. In the mid 24th century, Spock wrote to the Vulcan Science Academy about the possibility of Unification with their Sundered cousins, the Romulans. The Department of Extra-Vulcan Research responded to him, saying they found it illogical to consider Reunification and believed it was not possible. (TOS novel: Vulcan's Heart)