After three long years of hard work, my book has been published. It is called "The Dallas Zoo : A History". It starts in 1888 with its conception and ends with 2014. It's 778 pages long. You can now purchase it at Amazon for $33.25.
Congratulations! At almost 800 pages that is a monster of a book, but I suppose that you have combined your 4-5 shorter Dallas Zoo history books into a single publication.
Thanks! You are correct. I self-published the volumes as I went to motivate me to finish the project.