But if you looked a little closer at all those positive publications, there was a common denominator: the researchers, on the whole, worked for radium firms. As radium was such a rare and mysterious element, its commercial exploiters in fact controlled, to an almost monopolizing extent, its image and most of the knowledge about it. Many firms had their own radium-themed journals, which were distributed free to doctors, all full of optimistic research. The firms that profited from radium medicine were the primary producers and publishers of the positive literature.