Brian Michael Bendis series, written in parallel with All-New X-Men (1st series). Also published parallel but less directly related were X-Men (4th series) and Wolverine and the X-Men (1st series).
Series followed Cyclops and his group of "mutant revolutionaries," running the New Xavier School and operating out of the original Weapon X facility in Canada. Series ended with #35. It was followed four months later by a leacy-numbered #600, which served as Bendis' final X-Men issue.