Secret Service Dogs: The Heroes Who Protect the President of the United States, By Maria Goodavage, Clint Hill (Foreword)

 

Here's one I read in 2017 and commented about on Facebook:

Quick take on "Secret Service Dogs" by Goodavage: It's good. Quite readable and the author does an excellent job of showing not only the personalities of the handlers but some of the individual dogs themselves. Not very far into it yet but so far enjoying it thoroughly.