Spies, Scouts, And Secrets in the Gettysburg Campaign

Title:                      Spies, Scouts, And Secrets in the Gettysburg Campaign

Author:                 Thomas J. Ryan

Ryan, Thomas J. (2015). Spies, Scouts, And Secrets in the Gettysburg Campaign: How The Critical Role of Intelligence Impacted The Outcome of Lee’s Invasion of the North, June-July, 1863. El Dorado Hills, CA: Savas Beatie

LCCN:    2015000010

E475.51 .R93 2015


  • Prologue: Tullahoma: June 24-July 4, 1863 — Intelligence resources: Army of the Potomac — Intelligence resources: Army of Northern Virginia — Intelligence plans and operations — Analyzing the enemy’s intentions: mid-May to early June — Deciphering the enemy’s movements: June 3 to 7 — The invasion commences: struggling to outwit the opponent, June 8-13 — Searching for Lee: June 14-16 — Screening the army from prying eyes: June 17-21 — Absence of coordination undermines Lee’s objectives: June 22 to 25 — Maneuvering for advantage: June 26 to 27 — A spy brings news of the enemy: June 28 to 29 — All signs point to Gettysburg: June 30 to July 1 — Intense effort to gain the intelligence advantage: July 2 — Lee’s flawed assumptions: July 3 — Lee retreats as meade deliberates: July 4 to 5 — A battle of wits and a test of wills: July 6-11 — The controversial escape: July 12 to 14.


Date Posted:      October 3, 2016

Reviewed by Hayden B. Peake[1]

Most Civil War histories and memoirs that discuss the Battle of Gettysburg are concerned with the strategy and tactics of the battle and its impact on the politics of the war. Some do mention the problems created for General Lee when he lost contact with his cavalry commander, General J.E.B. Stuart, before the battle began. And some also discuss the role of scouts and the contribution of General Longstreet’s personal civilian agent, Henry Harrison. Spies, Scouts, and Secrets in the Gettysburg Campaign takes a different approach; it focuses on the intelligence aspects of the campaign from the Battle of Chancellorsville to Lee’s retreat in defeat, back across the Potomac River.

Civil War historian Thomas Ryan describes how intelligence was organized and employed by the northern and southern generals and the influence it had on the outcome. The north created the Bureau of Military Information (BMI)—the first organization of its kind in the US military—to collect and analyze intelligence for the commander, MG Joseph Hooker, and later General George Meade. The BMI employed agents, the Signal Corps, the Balloon Corps, the US Military Telegraph Service, the Cavalry, and special reconnaissance and sharpshooter units. It also prescribed mandatory practices to be followed at all levels when interrogating deserters, defectors, and POWs. The South also employed many of these techniques. But, with the exception of its Signal Corps, they were less formalized and depended too heavily on the cavalry for their implementation. General Lee did not create a “BMI” and was, in effect, his own intelligence analyst.

Ryan shows how Lee employed deception to prevent Hooker from realizing he was going to invade the North, and how Hooker, who didn’t always accept the intelligence from his BMI, eventually learned what was happening. Both generals had major difficulties from their cavalry commanders. Lee had to revise his original objective—to attack into Pennsylvania—after he lost contact with Stuart, who failed to keep track of the Union Army. Hooker’s cavalry commander, BG Alfred Pleasanton, often failed to follow orders and his reports on Lee’s Army were frequently erroneous, a factor contributing to Hooker’s resignation and the appointment of General Meade as Union commander.

Spies, Scouts, and Secrets in the Gettysburg Campaign illuminates how intelligence was collected and applied in more detail than any other book on the entire Gettysburg campaign. It is a valuable contribution to Civil War history.

[1] Peake, Hayden in The Intelligencer: Journal of U.S. Intelligence Studies (22, 2, Spring 2016, pp. 134-135). Hayden Peake is the Curator of the CIA’s Historical Intelligence Collection. He has served in the Directorate of Science and Technology and the Directorate of Operations. Most of these reviews appeared in recent unclassified editions of CIA’s Studies in Intelligence, Other reviews and articles may be found online at http://www.cia.gov

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