Mr. Brack was a wealthy industrialist and an alias used by the immortal Flint in 2239, when he bought the uninhabited planet Holberg 917G in the Omega system. (TOS: "Requiem for Methuselah")

Previous aliases of Flint
Akharin • Methuselah • Solomon • Alexander the Great • Lazarus • Merlin • Leonardo da Vinci • Johannes Brahms • Abramson • Brack