Philbrick has gone out of his way here to create as accurate a picture of the battle and the days leading up to it as can possibly be drawn. Given the logistical difficulties involved, this in itself is no small feat. By profiling Custer and those around him, as well as Sitting Bull and those in his circle, Philbrick shows just how the campaign shaped up, how Custer was undone both by his own ambitions and the various incapacities of those around him (and just how much good intelligence matters when you're out in unfamiliar territory!).
The book is made even better by Philbrick's personal observations about the land and territory around the battlefield; his descriptions of the topographical oddities that Custer and his men faced around the Little Bighorn valley definitely enhance the text in an important way; I felt like I understood the situation much more clearly after reading of his visit to the area.
Another interesting element of The Last Stand is Philbrick's treatment of the battle's aftermath, as we see those involved making their cases, spinning the events to reflect them in the most favorable light. Philbrick argues - and I think quite convincingly - that Custer's widow Libbie played a key role in creating the "last stand" motif.
No ground-breaking new interpretations of the battle or significant new sources are brought to bear here, but Philbrick knows how to tell a story well, and sometimes that's all that matters. His text, coupled with the large number of well-designed maps and lengthy sections of photographs, made this book work for me.