Towards the end of
Tom Strong, Alan Moore stopped writing the title and it was handed to a series of guest writers who each did one issue or one arc, including Brian Vaughan, Geoff Johns, Ed Brubaker, and even Michael Moorcock. Moore returned for the final issue though, to give his characters their proper send-off.
This issue has a significance within Moore's oeuvre. When it came out, Moore's work on all the other ABC titles had already wrapped up. As such, this was not only his farewell to Tom Strong but to the ABC line and mainstream comics, as well (as he's made clear in interview's that he's washed his hands of that scene).
It's a real delight. If only all swan songs could be this elegant and graceful.