1. The Indiana Jackass Regiment in the Civil War: A History of the 21st Infantry / 1st Heavy Artillery Regiment, with a Roster by Phillip E. Faller (McFarland, 2013).
The research, presentation, and content of this regimental history all look promising. The 21st was a bit of a multi-tool unit (eventually being formally converted to heavy artillery in 1863), and its area of operations in Louisiana and Alabama is a nice change from the typical theaters.
2. William B. Cushing in the Far East: A Civil War Naval Hero Abroad, 1865-1869 by Julian R. McQuistan (McFarland, 2013).
Aided greatly by Cushing's letters to his fiance, McQuiston recounts the officer's post-Civil War naval career at the helm of the USS Maumee, where, from a base in Hong Kong, vessel and crew enhanced the American trade and naval presence in Asia.