Today, a minute on such an obscure topic would be considered too long for most viewers.

With increased collection and study of the postal markings originating from such offices, the body of literature on this obscure topic may grow.

It's a vast jamboree of meetings on obscure topics and pleading special interests.

Because his favorite subjects include codes, puzzles, treasure hunts, secretive organizations and academic lectures on obscure topics, he tends to incorporate those into his novels.