Reported book mistakes, not yet fixed:

Problem 11.13: the word "Kindergartener" is misspelled twice (reported by Nicholas).
Problem 14.16: replace "rectangle" by "square" to avoid confusion (thanks Nicole).
Problem 14.16 is same as 3.21. Also, might move 3.23 to chapter 14 (noted by the author).
Solution labeled as one to problem 11.50: it is actually a solution to problem 11.49 (thank you Christy).

Other things needing improvement (noted by the author):
Chapter 12 needs to be revised and pictures in chapter 13 (in the text and in the solutions) need to be recreated so that the font for all variables is correct (will do so using tikz) - sorry, no time to do these things this semester, they will have to wait until next year.