I'm afraid I don't really understand this question. I am interpreting it as, "Why is the author giving it away for free instead of charging money for it". If th

I'm afraid I don't really understand this question. I am interpreting it as, "Why is the author giving it away for free instead of charging money for it". If that is not what you meant to ask, sorry! Anyway, if that is what you meant to ask: Well, I'm the author, so my answer may have some substance (-:. I have a good job and it pays me to have impact. I can have much more impact by giving away the book to people interested in learning. [º] [º] This is not 100% true. Over the years, people have told me they value a book more if it costs something. I am not looking to please them. In particular, I grew up in India and we could not afford fancy (but great) Western textbooks. If there's a student like me right now (whether in India or Indiana) who wants to learn from my book but for whom its cost is an obstacle, that would make me very sad. That's why all the books I have (co-)authored have been available for free. On the first edition's site [https://cs.brown.edu/~sk/Publications/Books/ProgLangs/2007-04-26/ https://cs.brown.edu/~sk/Publications/Books/ProgLangs/2007-0...] you can see the different models by which I have made the book available. They have netted me some modest revenue. But there's always a free option.