Russel Beatie's website lost a lot when it took down his draft chapters of unreleased volumes. (Not, before I nabbed a few pieces of his unreleased Volume III of Army of the Potomac, however).
Richard Miller (right) has a book coming out next month called Harvard’s Civil War: The History of the Twentieth Massachusetts Volunteer Infantry and you can sample it (obliquely) by reading a couple of related article on his website: "The Trouble wtih Brahmins:, Class and Ethnic Tensions in Massachusetts' Harvard Regiment" and "Brahmin Janissaries:, John A. Andrew Mobilizes Massachusetts' Upper Class for the Civil War."
There are more articles on this regiment, all well worth reading.
Free samples - always a good thing.