This is a postscript to Peter Mc's excellent post below celebrating the 148th anniversary of the publication of On the Origin of Species. Zoom in on the title page and you can see this:
For those of you who haven't yet had laser eye surgery, it reads 'By Charles Darwin, M.A., fellow of the Royal, Geological, Linnean, Etc., Societies; author of "Journal of Researches during H. M. S. Beagle's Voyage Round the World."'
Imagine being a fellow of so many societies that listing them becomes tedious so you finally give up and just write "Etc." after the first few. And then there's the Victorian version of "bestselling author of Voyage of the Beagle", which reminds us that this book was intended for a broad audience. In other words, Darwin was a writer of popular science in addition to being a "hard" scientist (an important fact to have handy if your science boss sneers at the idea of writing/speaking for a general audience). Also, notice the lack of "Dr." before or "Ph.D." after Darwin's name. Message: it doesn't take a PhD to do groundbreaking science (though it does help you get a job if you don't come from a moneyed family).