Rehabilitating the neomalthusian nightmare

I'm finally getting around to reading Jared Diamond's Collapse. Unlike his earlier Guns, Germs, and Steel, this one apparently has had mixed reviews from economists. I'm a big fan of the latter, and was drawn in to the former by the same enthralling and deceptively simple style. Now I'll just have to see whether the Diamond's arguments stand firm or fall over. One question: is it a Malthusian book as many decry? Just after reading the first chapter I know it's not that at all.