Soong, Dr. Noonien
As one of Earth's leading robotics scientists, Dr. Noonien Soong studied with Dr. Ira Graves, but slipped into obscurity in the early 24th century after failing to create an Asimov-like positronic brain. Only later was it discovered that this man of mystery had left an incredible legacy by doing so, working under an assumed name, on a private science colony in the Omicron Theta system.
Having created three models before building the imperfect Lore with emotions, Soong disassembled him and programmed Data in 2338 without them. In 2364, Soong was thought killed in the Crystalline Entity's attack on the colony, but three years later, a personal summons to Data revealed that Dr. Soong had survived the massacre. He escaped to a secret, solitary jungle lab on Terlina III to continue his research and perfect an emotion chip. Not knowing that Lore had been reassembled in 2364 by Data's U.S.S. Enterprise crewmates, the elderly Soong unwittingly called him as well, and mistakenly gave him Data's emotion chip. Soon after, Soong died by Lore's hand during one of android's dark rages.
Only after Soong's death was it known that he had married Julianna O'Donnell, on Mavala IV, in 2328. O'Donnell helped build all the androids, then escaped with Soong to the second lab. There, she died in an accident and was herself rebuilt in an android body, with transferred memories — a job so perfect that even she did not realize it and later left her husband to remarry, breaking his heart. Soong left a message for Data in his new emotion chip, detailing the story of Julianna, as well as an advanced 'dream' program.
Soong kept up with Data's career and legal debates, but did not know that Starfleet discovered Data. Soong wanted Data to be a cyberneticist or other scientist, following in his father's footsteps. Soong likened his creations to an artist's need for expression and a natural desire to procreate as a way to immortality.