To be released September 29, 2015.
I received an early uncorrected proofs copy of this book from the GoodReads First Reads Program.

I was thrilled to get the chance to read a new Butcher series!
The ever wonderful, Butcher wit and dialogue, add to that ... Magic, steampunk, privateers, talking cats and airships!!!
With a touch of swashbuckling, The Aeronaut's Windlass is a bit magical, a bit off worldly, and all action. It reminds me of the old high seas movies (or in this case high skies) with the ship to ship battles.
I will be re-reading this when it is released with the audiobook version.
Details:
Published September 29th 2015 by Roc
Jim Butcher’s The Aeronaut’s Windlass debuts at number 5. on the New York Times Best Sellers Hardcover Fiction List for Oct 11, 2015 - Oct 25, 2015.
Published September 29th 2015 by Roc
Jim Butcher’s The Aeronaut’s Windlass debuts at number 5. on the New York Times Best Sellers Hardcover Fiction List for Oct 11, 2015 - Oct 25, 2015.