Robin,
the Other half of the Dynamic Duo.
Dick Grayson of Earth-1
Born: floating date between c.1942 and c.1962.
Started career: floating date between c.1955 and c.1975
First comic book not clearly determined.
The transition from Golden Age to Siver Age (later designated Earth-2 and Earth-1) versions was unintentional, and had no clear splitting point. Robin's early history was much more consistant between versions than Superman's, but in some cases, character traits and continuity events that would later be ascribed specifically to different versions of Robin had actually been associated with a single Robin in a past story. Once the Earth 2 & 1 concept had been developed, the Earth-2 Robin was linked with the original appearance date while the Earth-1 Robin was kept roughly static by floating his past history. So, whenever the Earth-1 continuity comic book was published, Robin was born about 13-18 years before, and commenced his career at at around 13. Later Earth-1 stories gradually let Dick Grayson age from a child to a young adult, first as a more mature Robin, then as Nightwing he must've aged to his early 20s.
[This Dick Grayson's early history was almost identical to that of the Earth-2 Dick Grayson.]
When Dick went off to college, he began to act as Robin more independantly from Batman. In time, he became affiliated with a group of young heroes called the Teen Titans (later just the Titans). He eventually left school (much to Bruce Wayne's consternation) and adopted the costumed identity of Nightwing, which was almost a cross between the Batman and Robin costumes.
With his long heroic experience (by Titan age-group standards), great detective skills, and understanding of teamwork, Nightwing became leader of the Titans.
At the time of the Crisis on Infinite earths, Dick was involved in a deep relationship with Starfire, an alien princess and fellow Titans member, which was in jeopardy due to a politically arranged marriage on her home world.
The Earth-1 continuity ended with the Crisis in 1985. In the hypothetical future of Earth-1, a sort of anti-superhero mania would spread across the Earth in the late 1980s, which would drive almost all costumed heroes into retirement, or away from the Earth entirely by the end of the decade. Dick would apparently be forced into retirement as Nightwing. His relationship with Bruce apparently crumbled, and the two would not speak for nearly a decade before Bruce's faked "death" around 2000. It seems unlikely that Dick would ever learn of his old mentor's survival. But it is known that Bruce deeply missed the Dick Grayson Robin, even a decade after the death of his replacement.