The correct name of Darwin's work, which survived only the first edition, would suggest strongly that it was indeed aimed at a very specific audience.

"ON THE ORIGIN OF SPECIES BY NATURAL SELECTION" is a title which is specific to a learned treatise, aimed toward the attention of one's scientific peers.

The path of later publication as "The Origin of Species" may be much more general than that, but the writer's intention is very obviously specific.

Don T.