Data

Unable to feel emotions or understand certain human idiosyncrasies
Strived to be human, programmed with the logs & journals of the colonists
2338: Deactivated & left behind when the Crystalline Entity attacked the colony;
Discovered & accidentally activated by the crew of the USS Tripoli
2363: Assigned to the USS Enterprise-D as operations officer & second officer
2365: Won a trial that helped recognizing the sentience of androids
2366: Constructed his own daughter, Lal, she died shortly afterwards
2368: Given temporary command of the USS Sutherland during the Klingon Civil War
2369: Discovered a series of circuits that allowed him to experience dreams
2371: Installed an emotion chip that was created by Dr. Soong
2372: Assigned to the USS Enterprise-E as operations officer
2379: Killed in the destruction of the Reman warbird Scimitar
2399: Consciousness downloaded into a complex quantum simulation;
Subsequently terminated at his request
2401: Resurrected within a Golem body; became as close to human as possible
Helped save the Federation from a Borg attack