I have not read this book. I have a book called Common Ground for Christian Unity, but it is by Michael McKibben and dates from 1988. It is out of print, at least in this edition. I think it was reprinted by St. Ignatius of Antioch Press or something. It is very brief and to the point.
Can you kindly share some passsges from the Bajis Common Ground book? Does he say anything at all about the Filioque and Saint John 15:26?