Description based on vol. 2.
bk. 1. Collecting X-Men #53-54, Uncanny X-Men #334-335, Fantastic Four #414-415, Avengers #400-401, Onslaught : X-Men, Cable #34, and Incredible Hulk #444
bk. 2. Collecting Excalibur #100, Fantastic Four #415, X-Factor #125-126, Generation X #18, Wolverine #104, X-Men #55, Uncanny X-Men #336, Cable #35, and X-Force #58
bk. 3. Collecting Hulk #445, Iron Man #332, Avengers #402, Punisher #11, X-Man #19, Amazing Spider-Man #415, Green Goblin #12, Spider-Man #72, Fantastic Four #416 and Wolverine #105
bk. 4. Collecting Fantastic Four #416, X-Men #56, Onslaught: Marvel Universe, Cable #36, Uncanny X-Men #337, X-Men #57, Onslaught: epilogue, Iron Man #6 and X-Men: road to Onslaught.
X-Men: Onslaught : the complete epic. ISBN 9780785128267. Published by Marvel Publishing in 2008. Publication and catalogue information, links to buy online and reader comments.