Jenny: I did not use the map at all, but I didn't realize there was a command for getting a close-up view of documents (middle mouse button or, I think, the M button - it's stated in the manual that I never noticed until after I played the game!) What happens if you do the close-up view? Is it useful then? (Not that the catacombs were that difficult to get through...)
MaG, I tried that, and yes you can get into the catacombs without the map.

emily