First Issue #1 - April 1997
Last #81 - September 2003
Continued in New Thunderbolts
The Thunderbolts were first presented as superheroes like the Avengers, who became heroes to help protect the world when the Avengers were declared dead after the events of the 1996 "Onslaught" series. However the final page of the first issue revealed that the Thunderbolts were the Masters of Evil in disguise. Themes of redemption and the nature of heroism were often featured. In subsequent storylines, the group rejects their leader Baron Zemo and attempts to become heroes, eventually under the leadership of the Avenger Hawkeye.
After 81 issues, this series was retitled "New Thunderbolts (issues 82-99) and then was re-titled "Thunderbolts (2006 series) starting with #100.