Previous histories of the Civil War have explained victory or defeat in terms of the skill of commanders, the fighting qualities of the troops, and resources in men and materiel. Intelligence has been largely ignored, not because it wasn't critically important -- Lincoln called it the most difficult problem faced by the Union -- but because so little has been known about it. At the end of the war most of the intelligence records disappeared, and they remained hidden for almost a century, until Edwin Fishel uncovered them during the 40 years of research that has resulted in this monumental book. The Secret War for the Union is unique among Civil War histories in its reliance on original, previously unknown sources. It is the first book to examine in detail the impact of intelligence, and this intelligence explanation alters, sometimes radically, history's understanding of virtually every campaign. Both enthralling and authoritative, The Secret War for the Union is one of the most important books ever published about the Civil War. - Jacket flap. Most histories of the Civil War explain victory and defeat in terms of the skill of commanders and their troops. Intelligence records disappeared after the war, and thus a critically important element has largely been ignored. Fishel has unearthed substantial collections of such records, and his "intelligence explanation" radically alters history's understanding of the campaigns. The Secret War for the Union is one of the most important Civil War works ever published. Includes material on Allan Pinkerton and Rose Greenhow.

Foreword / Stephen W. Sears -- Introduction -- Twenty thousand potential spies -- First Bull Run -- "Known in Richmond in twenty-four hours" -- Phony war of 1861 -- Mr. Pinkerton's unique arithmetic -- "Outnumbered" on the peninsula -- Hard lessons from Professor Jackson -- Too little and too soon -- All the plans of the Rebels -- Luck runs out for Palmer and Stine -- Blind campaign of Fredericksburg -- New client for attorney Sharpe -- Ten days of southern hospitality -- Rebel spies are now second best -- Gray Fox swallows the bait -- Pinpoint intelligence and hairline planning -- Paralyzed by a real Jackson and a phantom Longstreet -- Lee's Army vanishes -- Pursuit -- Lost intelligence, lost battle -- Joe Hooker's magnificent error -- Reaping the Pennsylvania harvest -- Thirtieth of June -- Decision and victory -- Epilogue -- Appendixes. Successes and failures of Federal and Confederate intelligence -- A few lessons from (and about) Civil War intelligence -- Two strategic surprises -- Rose Greenhow's reports -- Strother's rejected warning of the enemy's stolen march -- The McClellan-Pinkerton estimates of Confederate numbers -- Pleasanton's role in the intelligence that started Hooker in pursuit of Lee -- Lee's crossing of the Potomac en route to Pennsylvania -- Comment on sources.