I promised a post on X-Men: First Class (the Parker comic, that is, not the film) at some point, and I never really got round to it. This is the last chance to look at it in the context that it is set, as Xavier just died (in a story that we are assured is "not a hoax"), and by the time it is revealed to be a hoax, Polaris and Havok have joined the team. So, our time with Xavier and the Original Five is about to end.
But, I'm getting ahead of myself.
X-Men: First Class was published from 2006 to 2010. Despite some claims otherwise, I don't see it as a serious attempt at a continuity implant within the original run. It is functionally the Marvel Adventures X-Men title (an imprint many of whose titles were written by Parker). Mostly single-issue stories, reasonably child-friendly, and heavy on the humour.
In my review for X-Men Season One (which occupies a similar narrative space of telling modernised stories set in the O5 era), I said First Class was a false nostalgia. I shall clarify what I mean. I don't mean that it doesn't fit in with continuity - I mean that the feeling of the stories is far more what we would like the 1960s X-Men to be like than it actually was. There is a preference for multi-issue stories at this point in the run, and they are tending to get longer. The school elements which get stressed in First Class are now almost entirely absent.
That this is consciously a false nostalgia can be seen from Parker's other series, Age of the Sentry. The Sentry is a mad weird idea, and I love him mostly for the sheer cheek involved. The Sentry was originally published in 2000, and presented as a forgotten superhero created by Stan Lee. This was eventually revealed as a hoax, but the joke was that the character had been forgotten, and the Marvel universe we knew should have had the Sentry (a sort of twisted Superman analogue) in it all along, and he fits nicely into the gaps (who was Reed Richards' best man, anyway?). This has become highly self-referential and metafictional, and subsequent appearances have, for example, featured a man named Paul Jenkins, who believes he created the character of the Sentry. This, and the relationship between the Sentry and the Void (his arch-enemy) has perhaps got a bit laboured in the comics, but that's beside the point.
One of the things that the original Sentry miniseries did was have tie-in Sentry Team-Up issues, depicting the Sentry's "original" interaction with Marvel heroes (one of them was with the X-Men, or rather with Angel, which I will do in due course). We then later got Parker's "Age of the Sentry", which is a Marvel Adventures-style superhero comic, based around a hero who never actually existed. So Parker knows exactly what he's doing. Nobody could write Age of the Sentry and not be intentionally recreating an imagined silver age. In fact, Age goes one step further by introducing a golden age Sentry, popped over from another dimension in a manner similar to DC's Earth-Two...
And so we get X-Men: First Class (and then later Wolverine: First Class. Perfectly formed, but twee.