This volume reprints four of the top 100 Marvel comic books ever, as voted on by fans. They are all great issues; the only problem is that some of them are part of multi-issue arcs, so you don't always get the full story in one volume. Still, these are some of the best and most important comic book issues ever, and are definitely worth reading for any Marvel fan.
Issues in this volume (and their importance):
25. X-Men (vol. 1) #141 Days of Future Past
24. Fantastic Four (vol. 1) #48 First appearance of Silver Surfer and Galactus
23. The Amazing Spider-Man (vol. 1) #1 First issue of Spider-Man in his own series; he meets the Fantastic Four; first appearance of Chameleon
22. Daredevil (vol. 1) #181 Death of Elektra Natchios