==Great Article!== 
 I never comment on Wikipedia, but I read just the introduction and was already very impressed. I am a graduate student and took differential topology, and boy do I wish I looked at this article earlier. It's simplicity and clarity in explaining what can normally be very complicated concepts is a model for Wikipedia pages. I admittedly do not know the technical details about why this page was removed from being a featured article candidate, but it is by far one of the best written articles I have ever come across on wikipedia. Thus, I would like to thank the writers and contributors; you guys deserve kudos.