The policy, which has been stable for a long time and which we intend to put in the FAQ, is that reposts are ok if an item hasn't had significant attention in the last year.

In this case, both available chapters of the book have had significant attention [1,2], so I think a post of its home page has to count as a dupe. If and when Chapter 3 appears, however, that will make a nice non-dupey post.

(Good luck with the book, Michael!)

1. https://news.ycombinator.com/item?id=6794308

2. https://news.ycombinator.com/item?id=7588158