These days, 'publication day' is a somewhat nebulous concept, but anyway, although it has been available from Amazon for a little while*, today is the official publication day of the mass-market paperback edition of In The Mouth of the Whale.
Happy birthday, little book. I hope those who go looking for you are able to find you; and I hope that some people who didn't know about you will find you too.
For the curious, there's more information here, along with some extracts.
*Edit - have been reminded that you can also buy it here, with free worldwide delivery.