In my third year at Caltech I was also asked to teach some classes about computers. A group of people said, you know, Caltech doesn't teach anything about computers, and we know that you're consulting to Burroughs, why don't you… why don't you think of… of giving a course, just… just to… to offer to Caltech? So I had also… then been a… giving a once… once only course, even before I graduated at Caltech, and they made the very unusual decision to hire me as an Assistant Professor after graduation. Usually a… a university won't hire its own graduates, except MIT. But… but usually, you know, it's… it’s considered bad to have… to have inbreeding, because a department can get bogged down in one… in one philosophy, and you usually want to bring in new blood. Well, Caltech, I guess, felt that I was sufficiently strange of blood that they… that it was okay to hire me too.

Now, meanwhile, in the… in the January of 1962, I'm in my second year of Caltech, and in my… my first year of marriage – we got married in the summer of '61 – so… so Jill and I had 6 months of wedded bliss, we started with our honeymoon, and then… and then we had a… a time before I was approached by Addison-Wesley to write a book about computer science… about computers. And in the January of '62, an editor from Addison-Wesley took me out to lunch, and said, ‘Don, we want… we need… we would like to invite you to write a book about compilers’. You know, compilers, this is this system… thing that I had done for Burroughs the previous year, and I had… I just finished.  ‘And… and, you know, you have been recommended to us as somebody who knows how to write compilers, and would you think… would you think about writing a book like that?’ So I'm one-and-a-half years into graduate school at the time, and doing consulting for Burroughs, but I… but, boy, I couldn't get the thought out of my mind. Wow, I love writing a book? I just, you know, I'd been working previously on… on newspapers, magazines, you know, writing a few articles. I enjoyed writing all the time, and… and I… and here was the publisher of my favorite textbooks, Addison-Wesley, was asking me to write a book for them. And so right away I went home and I jotted out the titles of 12 chapters I thought would be… would be good for a… for a book. And… and then… well, our marriage was still happy, but it was different, because I started concentrating on this book, for the next 40 years. I thought I could finish the book, you know, rather quickly. I… I have letters that I wrote in… in 1964 or 5. No, '64, I… I wrote a letter to somebody saying… ‘I'm sorry I can't visit Stanford University this year because I have to finish my book before my son is born’, you know. And… well now he's 40 years old, and I still haven't finished the book, but… but that's just… we'll… we’ll get to that. But I thought I… I thought I would finish… I had no idea how long it would take me to… to, you know, to write this book. They asked me to write a book about compilers, but I… I thought, well, wait a minute, there's a lot of other stuff goes on in computer programming that you… that you also need to know before you finish your compiler, so I said, would you mind if I put in chapters about these other aspects of computer programming? And they said, no, go right ahead. Okay, so this book, we… I… we decided to call it The Art of Computer Programming. They liked that title.
 
My original motivation for writing it was not only that I liked the idea of writing books, but because I could see a big need for such a book. There was nothing like it. In fact, although I had written several compilers, and I knew a lot about compilers, I hadn't invented any of the ideas in those compilers. I had just applied ideas that I had learned from other people. And so everybody else I could think of, who was able to write a book about compilers, I… I also, as far as I could see, they were pretty biased and slanted. They would… they would mention their own method, and they wouldn't mention anybody else's method. But I was the only person I knew who… who didn't have this axe to grind. I had never invented anything myself, I was just a writer, I could… I could present everybody else's idea in a way that was consistent, and wouldn't… and wouldn’t distort the picture the way they would, if they wrote it. You know, and anyway, this is in the back of my mind, when I'm saying, yes, I want to write this book. I wrote the book because I didn't have any… because I felt that I was… that I was fairly good at writing, and that I would be able to balance the… the accounts that other people who had had more of a stake in it would… would. And of course as soon as I got started writing it, I…I naturally would discover a few things too, and I… and I had my… and I developed my own biases and… and distorted. But… and so I didn't succeed in my… in my goal, of making the unbiased presentation, but… but I have to say that quite frankly, I did believe originally that that was my main reason for… for writing the book.  It was needed, such a book was necessary, and I couldn't think of anybody else who would be able to present if fair… the story fairly. Not that I did fairly myself later, but at least I couldn't think of anybody else who would… who would do it. And I began to… so I began writing drafts of the material, starting then in… in the summer of ‘62. I had classes of… during the beginning of ’62… but I started… I started drafting material for The Art of Computer Programming, and… and the course that I wound up teaching at Caltech, during… during my third year of graduate school, was based on these notes that I had made, preliminary to The Art of Computer Programming.