After "disassembling" his team in the last four issues of Avengers, Brian Michael Bendis launched this first New Avengers series, comprised of many of his favorite characters. The events of the next few years of the series comprised the launching point for major Marvel events, from Civil War, Secret Invasion, Dark Reign and the Siege.
After such a dark tone, Bendis wanted a fresh start and ended this run with #64 and relaunching with a second New Avengers series, written in tandem with a new "adjectiveless" Avengers series.