Very close to the movie with only a few alterations in character. Pretty much a late Empire character sketch...reminded me of Boethius and Roman Christians after the fall of Rome...withdrawal from the world.
I think there was something unwholesome about Shangri-La. Instead of staying and fighting for a better world the monks and Conway decide to runaway from it to supposedly save the best of it for after the end of the coming dark age...and they imprison anyone who wants to leave (Conway's change of heart near the end makes no sense for the character...cheesy trope to complete the plot). There's always an apocalypse around the corner for yahoos like Conway (today it's 2012). This is late Empire psychology...Roman, British, American. Something feminine (in the psychological sense made popular about another intellectual wannabe ~ Jung) about the whole sodding mess.
Sorry to be so harsh but defeatist literature like this really pisses me off.
Where the book shines is as a character study of late Empire psychology and as a manifestation of a type made cliche by writers such as Kipling.
My recommendation...see the late '30s movie with Ronald Colman and don't read the book.