I have experience with Lisp, Java, Scheme and Clojure. I am surprised at how vehemently people are pushing back on James (the author). I tried coding in Clojure and found myself working very hard at things that would have been straight forward in Lisp. Could it have been done in Clojure - answer is "yes!". But i didnt want to get sidetracked thinking about how to make programming language work for me rather than actually work on the task.