Thanks to everyone who wrote to let me know that Essential PHP Security was Slashdotted yesterday. Slashdot still amazes me. I think the book's Amazon.com Sales Rank is a testament to the power of Slashdot.
He notes that the book has been very well recieved (at #354 in the Books section on Amazon) and has garnered some great reviews as well. It's great to see that the community is snatching up this great resource. It can only help to further the cause of enhanced security in PHP applications overall.