Doctor Ira Graves, PhD, was a Human molecular cyberneticist. Graves was believed to be one of the finest scientific minds of his time and was a recipient of the Zee-Magnees Prize. Graves claimed to have been a mentor to Doctor Noonian Soong, suggesting that made him "grandfather" to Soong's android creation, Data. Late in his life, Graves retired to Gravesworld where he began to suffer from Darnay's disease. He lived in virtual solitude, except for his assistant Kareen Brianon, who he had secretly fallen in love with, regretting the difference in their respective ages.
Doctor Graves in the main computer
In 2365, knowing he was close to death, Graves transferred his consciousness to Data, giving him control of Data's body, after which his own body died. Although Graves initially tried to hide this fact, it was quickly discovered. Graves' mind was removed from Data and transferred to the USS Enterprise-D's main computer allowing his vast knowledge to be stored permanently, although the Human element could not be salvaged. (TNG: "The Schizoid Man")
Background
Doctor Graves was played by W. Morgan Sheppard in his proper human form and by Brent Spiner when Graves was in control of Data's body.
Graves' receipt of the Zee-Magnees Prize was not established in dialogue, but a certificate was seen in his laboratory. This was a reference to "The Ultimate Computer", where the prize was first mentioned.
Given that Soong appeared to be several years older than Graves in "Brothers", Graves may have been lying about Soong being his student.
The title to the episode is the same as an episode from the 1960s British science fiction show The Prisoner whose star, Patrick McGoohan, was originally intended to play the part of Graves. (Star Trek Encyclopedia)
The computerized Ira Graves featured several in-jokes, including another reference to the Japanese series Dirty Pair in the form of "Kal(Yu/RJ) DP (Angle)". (See 'Kei', 'Yuri', 'Dirty Pair', and 'Lovely Angels')