While the battle of Gettysburg remains the centerpiece of the June/July campaign of 1863, there is an increasing interest in less-studied peripheral events that were an integral part of the operation. One such event occurred the day before the battle of Gettysburg began - the cavalry action on June 30, 1863 at Hanover, Pa. This important event is worth examining more closely since it played a key role in the campaign's outcome: it deflected Jeb Stuart's main cavalry units away from the impending battle at Gettysburg and helped prevent it from uniting and participating with General Robert E. Lee's main battle force until the last day at Gettysburg. Although relatively little information is contained in the official reports on the action at Hanover, especially on the Confederate side, author John Krepps has constructed a fascinating account about the action at Hanover from many previously unpublished, but important, sources often overlooked. They include soldiers' diaries and letters, and civilian eyewitness accounts, including damage claims filed afterwards. This detailed narrative is presented with comprehensive maps that bring clarity to this little written about subject.