Gary Shelton was a Manticoran citizen and an officer of the Sphinx Forestry Service. His treecat name was "Old Authority".
He served as Chief Ranger in 1518 PD, when humans first became aware of the existence of the sapient treecat species. (SK1, Tech Bu9)
In August 1922 PD, he decided to send Harrington and Zivonik to an accelerated three-month training program at Landing University of Manticore. (SK3)