No it isn't. The book has been available since much prior to the notice about royalties being put up.
I have a single correspondence with the author about compensating him for his effort (I used the online edition) to learn lisp and he refused -- as the publisher has first rights to collect monies on the book -- , I am inclined not to even fleetingly question his judgment in posting the book online.
I have a single correspondence with the author about compensating him for his effort (I used the online edition) to learn lisp and he refused -- as the publisher has first rights to collect monies on the book -- , I am inclined not to even fleetingly question his judgment in posting the book online.