Thanks for your interest. In sum, I posit that if the Union had won overwhelmingly at Antietam (a very real possibility), complete with the surrender of Lee and his entire army, it might have led to a total collapse of the Confederate military effort. At that point, some Confederate leaders would have recommended that the South accept the terms of the Emancipation Proclamation. The latter freed the slaves only in states in rebellion as of January 1, 1863. If the states reversed their resolutions of secession before that, they could keep slavery (or according to the terms of the Proclamation, be compensated if them manumitted the slaves). This, I note, would be the ironic result of an overwhelming Union victory. Granted it is a speculation, but that is what alternative history is supposed to be -- "What if"? I would also note that this book is an outgrowth of my talks to Civil War Round Tables about my first book, "Citizen-General: Jacob Dolson Cox and the Civil War Era," which was published in 2014 by Ohio University Press. When speaking about Cox, I would note that he commanded the left flank of the Union at Antietam, and if he had attacked an hour earlier than he did, Lee would have not been able to defend against him -- and A.P. Hill would have arrived an hour too late.
Hope that helps the readership to understand the new book. Any questions? Buy the book!! All the best, Gene