When Roger Moore took over as James Bond in 1973's Live and Let Die, the franchise had been weathering some rough seas. Sean Connery quit after You Only Live Twice, to be followed by On Her Majesty's Secret Service with George Lazenby. Lazenby's performance satisfied no one, including himself, so a large check was waved in front of Connery to get him back for Diamonds Are Forever. He was done again. So Roger Moore, known at that point as television's Simon Templar from The Saint, took up the Walther PPK and license to kill, with the movies taking some more comedic turns to match the smoother and suaver Moore.
Everyone's got their own opinion, but I've held Live and Let Die and its successor The Man With the Golden Gun to be two of the weakest films in the franchise. They're nowhere near as bad as Moonraker or Die Another Day with Pierce Brosnan, but I can skip them without qualm. Things did not look good for the Moore era as Bond (Moore's final two outings, Octopussy and View to a Kill, are also forgettable).
But his other two entries, The Spy Who Loved Me and For Your Eyes Only, were two of the better movies in this long-lasting franchise. Moore kept his unflappable cool but the storylines, both of which involved strong female leads with driven agendas of their own, added just enough grit to give them some real impact. They bookend Moonraker, which indicates how important a decent story that's not too silly is to a Bond movie.
Moore had the ability to not take himself too seriously, which helped leaven the often-clunky narratives of the Bond movies. Even his turkeys have a few shining moments.
After finishing with Bond in 1985, Moore acted in a few movies and other roles but spent much of his time working for UNICEF and other charities. He died today at the age of 89.