The Works of Charles Darwin, Volume 10 The Foundations of the Origin of the Species: Two Essays Written in 1842 and 1844

"Are they needed? To be sure. The Darwinian industry, industrious though it is, has failed to provide texts of more than a handful of Darwin's books. If you want to know what Darwin said about barnacles (still an essential reference to cirripedists, apart from any historical importance) you are forced to search shelves, or wait while someone does it for you; some have been in print for a century; various reprints have appeared and since vanished." - Eric Korn (Times Literary Supplement)