I finished the 3:16 book, I finished Concrete Mathematics. I still can't get... get going back on The Art of Computer Programming because there's one more thing I have to do and it's called the Stanford GraphBase. And this is... this is a collection of literate programs that are... are to be used for standard examples that would be used in Volume Four of The Art of Computer Programming. So that took another couple of years to... to get that done right, it was... it was necessary to have this out first before the book was there so... so that the, I'd be able to finish other projects with other people around the world contributing since they could use the Stanford GraphBase to... to help. Finally then, about 1995 I'm able to open the door of the room where I had been throwing all the new material for The Art of Computer Programming for 15 years. While I'm working on TeX I'd really had no time much to think about it so... so when I get something in the mail relevant to Volume Four, Volume Five or so, I would just throw it into a pile and then I had boxes and boxes, so finally it had... had accumulated to about 17 linear feet of... of material. And... and besides I had all of the material I had collected in previous years.  So I decided I just have to reorganise it all and that took another year... more than a year to go through everything, every scrap of paper that had come in and... and put it in... in a good place, make a computer index so that I could find everything, make... put it into thousands of little file folders and... and also correct all the errors known in Volumes One, Two and Three. People had been writing to me, I had letters from 1981, 1982 that I hadn't answered yet, reporting on errors in Volumes One, Two and Three.  So I wrote checks for all... to all these people with interest from the day of the, you know, I had a little computer program that computed these interest rates and I had a mistake in it so I think I paid a bit too much interest there. But anyway I sent out hundreds of checks and... and got... and had a big errata list for The Art of Computer Programming for Volumes One, Two, and Three and this I could typeset with TeX and... and have it typeset correctly. All these... all these years people were still buying the books at a steady rate in the book stores, they're buying the... like Volume One, Volume Three, they're buying the edition that was done from... in the '70s but, you know, like the 30th printing, the 40th printing. And it's still, you know,... each... each of the books are still selling at a rate of about 4000 books a year, something like that. And Volume Two was the edition of 1981, the one that I couldn't stand the numerals in but, you know, the... the mathematical material was okay. When the... when my Computers and Typesetting series of books, those five volumes came out, that was all done with the new fonts, with the correct... with the correct typography and so... with my Concrete Mathematics book I was able to use a new font designed by Herman Zapf and for the 3:16 book I have... I had another font that I had worked on so I had... So it was only The Art of Computer Programming that had ugly typography by this time and still I... I didn't want to, you know, it's been taking me so long to get back to... to writing Volume Four, how could I... how could I stop and redo Volumes One, Two and Three without... without waiting still longer? So, to the rescue came Silvio Levy who lives in Berkeley, who was... was very active in... in many projects of mathematics and he's now the librarian at the Math Sciences Research Institute. And... but he... he was a... a big fan of TeX and he and I created the CWEB system of... of literate programming using C as a programming language instead of Pascal. So Sylvio, some... the errata list for One, Two and Three... and he decided, pro bono, that he would typeset Volumes One, Two and Three in... in TeX and he would ask Addison-Wesley, the publishers, to... to pay him nominal amount for this to which they, of course, readily agreed. And... and he and his wife, Sheila, did the proofreading and they did a marvellous job going through all three volumes and incorporating all the errata in my errata list. And then it didn't take me long to - I mean it took me three or four months, but not really anything near what it would have taken to... for me to do all the work myself - so that we could have, finally, as 1997/1998, we could finally have The Art of Computer Programming brought up to date with... with decent typesetting and... and so... with all the, you know, 20 years of... of improvements that had been in my files, now incorporated into the text.