I just heard from my editor at Capstone. Unfortunately, the Racing for History series has been pulled from their list indefinitely. They hope to bring the set back on a future list, but for now, my book - which was part of that series - is on hold.
I had a great experience writing this book, as most of you know! I'm hoping to have another chance to work with Capstone.
In the meantime, just keep swimming, right? I'm going to the NESCBWI conference in April (New England Society for Children's Book Writing and Illustrating), and I have a critique lined up for a picture book that I'm working on.