Halsey: Assuming you mean a first Titanic book, I'd have to recommend
Walter Lord's "A Night to Remember". It's the definitive "mother of all Titanic books" and the one that sucked most of us into this particular vortex. ;^)
If you're looking for a 1912 contemporary, first-person perspective, both Lawrence Beesley (a 2nd Class Passenger) and Colonel Archibald Gracie (1st Class) wrote personal narratives at the time that are really stunning work. (
Walter Lord himself relied heavily on both for some of his information.)
All of the above (in various formats) are pretty widely available through Amazon.com, Barnes and Noble [B&N.com], and various discounters. Colonel Gracie's account (originally titled "The Truth about Titanic") is also available in combination with Jack Thayer's later reminiscences, in a dual publication entitled "Titanic: A Survivor's Story". (For a teen especially, Jack's recollections are very poignant; he was only 17 at the time of the disaster, and lost his father as a result.)
Short of reading the Inquiry transcripts per se, it's pretty hard to get any closer to those events from an eyewitness perspective. And though some of the technical details were ultimately incorrect -- both Gracie and Beesley, for instance, believed the ship went down intact -- there's nothing quite like that feeling of "being there". (Of course,
Walter Lord also conveys the impression splendidly, even though he wasn't there.)
Cheers,
John
P.S. If you pursue "A Night to Remember", keep in mind that the widely available (and very reasonably priced) "mass market paperback" [Bantam?] omits the Index that's present in other editions; there are a few complete ones out there, most easily located online, though they cost slightly more. (None of the contemporary accounts were ever indexed.)