John Hill Brinton (18321907) met, observed, and commented on practically the entire hierarchy of the Union army; serving as medical director for Ulysses S. Grant, he came into contact with Philip H. Sheridan, John C. Fremont, Henry W. Halleck, William A. Hammond, D. C. Buell, John A. Rawlins, James Birdseye McPherson, C. F. Smith, John A. McClernand, William S. Rosecrans, and his first cousin George Brinton McClellan. John Y. Simon points out in his foreword that Brinton was one of the first to write about a relatively obscure Grant early in the war:

"Brinton found a quiet and...