It was big book, I forget now the number of pages, something like 700 or 800 or so, and everybody said, well, couldn't you shorten it a little bit? And I looked at it and I saw that for every phenomenon, for every… as evidence for everything that I claimed I always gave five or six or 10 examples as evidence. And I saw that, yes indeed, I could shorten it very considerably, and so I brought out an edition which was also very readable because I got not a science editor in Harvard  to helped me with the volume, this abridgement, but the English language editor. And I said to her, ‘Any sentence you don't understand, any paragraph you don't understand, tell me and then I will see whether I can make it more easily explicable’, except in a few cases where she simply didn't know the Mendelian Laws or something like that. So it was a very readable volume, came out as Populations, Species, and Evolution. However, I had over-emphasized the fact that it was abridged because at the same time I revised a great many chapters and, in… in a few cases, it was quite a drastic revision.