Currently Reading: X-Men: The Age of Apocalypse Omnibus
When Legion, the son of Charles Xavier, attempts to go back in time to kill off Erik Lensherr before he becomes Magneto in order to allow his father to live an easier life, he accidentally kills his own father, creating a temporal paradigm which causes the timeline as we know it to change. With Xavier not around to form the X-Men the team is instead formed by Magneto in an attempt to make his friends dying dream come true: to unify mutant and human kind.
The omnibus collects the entire epic which spanned the X-franchise for four months creating one of the most well renowned X-Events of all time. With the current focus on the AoA in Rick Remender’s Uncanny X-Force and the new Age of Apocalypse ongoing series by David Lapham, this is the perfect place for comic fans to become acquainted with the event in one huge volume. 
Note: Reportedly there will be a companion to this omnibus collecting aftermath material, so I’ll be looking forward to that in the near-ish future. 

Currently Reading: X-Men: The Age of Apocalypse Omnibus

When Legion, the son of Charles Xavier, attempts to go back in time to kill off Erik Lensherr before he becomes Magneto in order to allow his father to live an easier life, he accidentally kills his own father, creating a temporal paradigm which causes the timeline as we know it to change. With Xavier not around to form the X-Men the team is instead formed by Magneto in an attempt to make his friends dying dream come true: to unify mutant and human kind.

The omnibus collects the entire epic which spanned the X-franchise for four months creating one of the most well renowned X-Events of all time. With the current focus on the AoA in Rick Remender’s Uncanny X-Force and the new Age of Apocalypse ongoing series by David Lapham, this is the perfect place for comic fans to become acquainted with the event in one huge volume. 

Note: Reportedly there will be a companion to this omnibus collecting aftermath material, so I’ll be looking forward to that in the near-ish future.