One of the better Essentials volumes, simply for the diverse art styles. The original X-Men title was beginning it's way out (and was nearly canceled entirely after issue #66, when it became a reprint title), but that meant there could be a lot of experimentation by writers and artists. This volume has such diverse artists as Werner Roth, Don Heck, Ross Andru, Jim Steranko and Barry Windsor-Smith handling things. Storyline highlights include the X-Men graduating into their new costumes, the finale of the Factor Three story, the first Cobalt Man tale, and the origins of the X-Men featurette. This is one of the Marvel Essentials volumes that I can definitely recommend.