Now, it so happens that those lectures were taped, and later I was approached by the people who run or ran the Rockefeller University Press; they said, 'Could we make a book out of this?' I said, 'No way, I'm much too busy doing research.' I was still very active in the lab at that time. 'No way I'm not going to spend my time writing a book', and so, okay, they let the matter rest until a few years later. A young man from Argentina came to visit the university and he had a sort of double job – he worked with a  well... well-known cell and molecular biologist in Argentina called De Robertis but at the same time he was something of a journalist; he wrote science articles for newspapers. And he heard about those tapes and said, 'Oh, could I edit them?' I said, 'Well, why not?' And so he started transcribing the tapes and rewriting some of the stuff and he sent it to me. And I can't say I was appalled but I didn't recognise my own writing or my own stuff and so I started... I started correcting and rewriting and after having done so for one or two chapters, I said to him, 'Listen, it's impossible – either I have to rewrite the whole thing or you drop it', so he dropped the project. But I sort of got caught in the act and started rewriting the whole thing. Now that took several years because I really had to start learning first. Because my field was biochemistry... I knew a little about biochemistry; cell biology, as I said before, I knew only those parts that I was personally working on but then I really had to start reading and studying, well, all the other parts of the cell. I had to start making illustrations – this book has about 200 illustrations, many of them actually drawn by myself and then redrawn by an artist. I had a very pleasant collaboration with an illustrator called Neil Hardy, and he actually came to Belgium and worked with me for several days. And it was rather amusing; it was an amusing experience because somehow those drawings that I made were very crude drawings, of course – I made them simply by imagining molecules, because these were really scale models of molecules. I imagined those things, or imagined chromosomes or things like that. But he had to build... he was an artist, a professional – he had to build a paper model of the molecule before he could start drawing... is a very interesting difference. Well, anyway, I had to find electron micrographs and photographs, I even included a few works of art, I had a Henry Moore to compare with the structure of mitochondria, a Hans Arp to compare with the structure of a protein, and so on. Anyway, it turned out to be a big undertaking, especially since I was still busy doing research at the same time, but I really enjoyed it and I... I enjoyed really beginning to learn something. It was sort of an experience, like what I had been doing all my life had been digging, and the deeper you dig, the narrower your scope and finally I was down there in that little tunnel and just looking at lysosomes and peroxisomes and so, slowly, I was moving up and looking around and saying, 'My God, but this is also interesting, this is fascinating and so on.' So it was... it was a tremendously gratifying experience and the end result was a book called A Guided Tour of a Living Cell – many illustrations; appeared I think in 1984. And it appeared as... as a second book in a new collection called The Scientific American Library, so I had a very good publisher for the book and in fact made good friends, thanks to this publisher, and I think the book was moderately successful because there was a subscription organised by The Scientific American for all the books of this library.