Alpha (X-Men: The Age of Apocalypse, Volume 1)

Charles Xavier is dead - killed twenty years in the past during a time-travel accident - and the world created by his absence is a nightmare! Apocalypse rules with an iron fist, ruthlessly enforcing his dictum that only the strong shall survive. But hidden in the long shadow of En Sabah Nur is a group of ragtag freedom fighters led by Xavier's oldest friend, Magneto: the X-Men! When Bishop, last survivor of the true Marvel Universe, explains how the world went wrong, these embittered mutants and their tenuous allies must risk everything to put things right! 

Collecting: Uncanny X-Men (1981) #320-321, X-Men (1991) #40-41, Cable (1993) #20, X-Men Alpha, Generation Next #1, Astonishing X-Men (1995) #1, Gambit And The X-Ternals #1, Weapon X (1995) #1, Factor X #1, X-Man #1, X-Calibre #1, Amazing X-Men (1995) #1, X-Men: Age Of Apocalypse Ashcan Edition