[mixu]

Thanks for your kind words. There are definitely some cases where the topics could be reordered for greater clarity and I'll revisit them in the next iteration of the book based on the things people have pointed out (again, after a hiatus).

One of the challenges is to find the right balance between rigorous exposition one the one hand and keeping a brisk pace on the other (after all, writing for the web is different from writing a textbook). So I am grateful for all the input I've received thus far but it has definitely been challenging to find editors and reviewers - in particular because this is an unpaid effort on my part.