Gary Mathis is correct the book was " 'I Acted From Principle': The Civil War Diary of Dr. William McPheeters, ConfederateSurgeon in the Trans-Mississippi". (Cynthia Pitcock & Bill Gurley, eds., University of Arkansas Press, 2002). McPheeters' account of the Missouri Raid is one of the best first had accounts you will find.
Bill Gurley