June 1 is when the pre-ordering for the Swords & Wizardry Tome of Horrors will be ending, and it's a somewhat important deadline because not very many additional books are going to get printed. The up front cost of these things is so high that we're only going to sort of "round the number up" from however many are ordered. There might be as many as 49 extras, but there might be fewer. So if you are planning to get the book, make sure you order it before June 1. There will only be a very few additional copies for sale to those who don't order in advance.
Note: this is only about the print copy - the pdf will remain available afterwards in the beautifully unlimited quantity that the internet allows.