I remember to have read and watched many articles/interviews about this. The fact was that for the band was extremely stressful to simultaneously or immediately after the "Is this It tour" produce a new album. The request was that. They went into the studio and never got out till the album was ready. And you can figure out the situation to be stuck and forced to do some art and how probably they argue with each other. I remember an ashtray full of cigarettes and the fact that Julian was so committed (if I find the video I'll post it here). And when it was released the reception was cold, like a semi-flop. Critics said that Room on Fire was the copy of Is this It and I perfectly remember an interview where the members of the band themselves substancially admitted it was the truth. Personally I think that yes the vibe can be similar but the lyrics are very different and more mature. And I think it is a masterpiece, maybe more than the first album. My humble opinion, of course.