Why wait until next April.
Brett of TOCWOC and Perry of the Shiloh Discussion Group are now hosting a thread wherein members submit their top/favorite seven books written about the battle [book thread URL here]. As of this writing a number of interesting lists have been submitted.
1. Shiloh: Bloody April by Wiley Sword (Morningside, 2001 revised edition).
Like all book length narrative histories of Shiloh, Sword's account of the second day of fighting is meager in comparison to the first [perhaps Cozzens will be the first to remedy this], but his book remains my favorite, still the best tactical treatment of the fighting around.
2. Shiloh: The Battle That Changed the Civil War by Larry J. Daniel (Simon & Schuster, 1997).
While I prefer Sword's account of the April 6 fighting, I would consider Daniel's book the best overall treatment of the campaign and battle.
3. Shiloh and the Western Campaign of 1862 by O. Edward Cunningham, ed. by Gary D. Joiner and Timothy B. Smith (Savas Beatie, 2007).
Since its publication, much has been made of Cunningham's writing style and the judicious manner in which each aspect of the battle is examined (i.e. no section's importance is 'hyped' to the detriment of another), but I still stubbornly cling to Sword and Daniel.
4. The Battle of Shiloh and the Organizations Engaged by D.W. Reed (Univ. of Tennessee Press, 2008).
Deeply influential in the battle's historical presentation, both in print and battlefield park interpretation, Reed cannot be overlooked. His book is a still-useful classic, and the large color maps [existing as pull outs in the earlier editions, but on CD in the latest] are an added resource.
5. Seeing the Elephant: Raw Recruits and the Battle of Shiloh by Joseph Allan Frank and George A. Reaves (Greenwood, 1989).
Draws upon a large volume and variety of primary source materials (from both sides) to provide readers with a personalized view of the battle, and within an analytical-statistical framework.
6. The Timberclads in the Civil War: The Lexington, Conestoga, and Tyler on the Western Waters by Myron J. Smith (McFarland, 2008).
Smith's study isn't a 'Shiloh book' by the strictest definition, but its coverage of the naval aspects of the Shiloh campaign and battle is presented in unmatched detail.
7. Shiloh: A Battlefield Guide by Mark Grimsley and Steven Woodworth (Bison, 2006).
The best of the Shiloh guidebooks, from the best current series (This Hallowed Ground) of guidebooks.
Another mention: I can't in good conscience include a book that I haven't seen or read on my list, but, thanks to the SDG, I've heard such good things about Shiloh, Shells, and Artillery Units by George F. Witham (Riverside Press, 1980) that I wanted to at least mention it. Plus, I can't resist a good artillery book of any kind. Hopefully, it will be reprinted someday (which, of course, will happen the day after I add an overpriced used copy to my library).