The cover signature reads "Byrning Bright".
Continues in the next story. The story follows up on events in The X-Men (Marvel, 1963 series) #137 (September 1980). In particular, pages 2 and 3 are a new version of pages 22 and 23 of that X-Men issue, with the dialogue being largely the same (hence the Claremont script credit).
Continued from the previous story.