> This book takes an historical perspective. I enjoyed the return to typing in upper case very much! Ancient LISP in particular is nice to type, because there

> This book takes an historical perspective. I enjoyed the return to typing in upper case very much! Ancient LISP in particular is nice to type, because there are only letters and the occasional dash, asterisk and parenthesis. All the special characters in modern languages really hurt my fingers! >One can easily represent trees by a notation that does away with most parentheses, but instead they've become a loyalty test. But can you copy or delete an expression from that other representation by paren-matching in your editor? To me (and others I guess) this was not much of an initiation ritual. I fell in love with parentheses on first sight. > $40 made me think. I get that! And to be honest, writing becomes more painful as I grow older, so I adjusted the price a bit to compensate for that. So far the sales numbers suggest that people are willing to spend the money. BTW, the PDF and paperback generate the same royalties (as with all of my books). The price difference is the production cost of the physical book. So you pay the same for the content in either case.