This book examines the extent to which General Robert E. Lee adequately delineated and conveyed his intent for the campaign into Pennsylvania in the Summer of 1863. The argument is made and defended that General Lee did not have the overall intent of the campaign firmly defined in his own mind. Failure to convey commander's intent caused his subordinates to operate without unity of effort. This led to confusion throughout the campaign and ultimately disaster at the Battle of Gettysburg. The book discusses General Lee's correspondence and conversations which provide contradictory views of his intent for the campaign. The book then reviews the execution of the march into Pennsylvania and demonstrates various instances in which Lee's Corps Commanders were confused by the lack of well defined commander's intent. The actual battle at Gettysburg is discussed only briefly and is used only todemonstrate the end result of the confusion which is evident throughout the operation. The book concludes by discussing the applicability of the lessons learned to a modern day joint commander.