His book, "Software Foundations" is here:<p><a href="http://www.cis.upenn.edu/~bcpierce/sf/" rel="nofollow">http://www.cis.upenn.edu/~bcpierce/sf/</a><p>And there's a discussion about the book from a year ago:<p><a href="https://news.ycombinator.com/item?id=7824793" rel="nofollow">https://news.ycombinator.com/item?id=7824793</a>