It’s been common knowledge since “The Bishop Revival” aired that the Observer appeared in the episode outside the diner right before Alfred Hoffman set off selective toxin #2, which killed everyone with brown eyes. But don’t worry, Observer-lovers. The Observer’s eyes are green, and he was never in any danger at all.
And has anyone else noted that whenever we see the Observer within the episode, he’s hardly ever actually observing? He’s simply walking past. Could his presence actually be the catalyst for these events, instead of vice-versa? (After all, the general in “Fracture,” seemed to be under the impression that the Observers were going to kill us all).
In any case, here’s what we saw of Mr. September in “The Bishop Revival.” If you’re having trouble finding him, look just to the right of the little girl’s face in the screen capture below.

Sam McPherson began writing for Walter's Lab in August 2009. He also writes for the sites TVOvermind, MovieOvermind and SpoilerTV, in addition to being an administrator on Lostpedia since March 2009. Sam's favorite shows are Lost, Fringe, Doctor Who, Flight of the Conchords, FlashForward, True Blood, and Monty Python's Flying Circus. Follow him on Twitter (@mcphersonator) or send him an email (sammcpherson@tvovermind.com).

[...] In any case, here’s what we saw of Mr. September in “The Bishop Revival.” If you’re having trouble finding him, look just to the right of the little girl’s face in the screen capture below. See larger image. [...]