1. Steve Berry's Novel (Most Common Association):

   • Author: Steve Berry
   • Series: Part of the popular Cotton Malone series (Book 11).
   • Genre: Historical thriller, mystery, adventure.
   • Plot: Cotton Malone, retired US Department of Justice operative, is drawn into a dangerous quest involving the Knights of the Golden Circle (KGC), a real historical secret society from the mid-1800s. Malone races against a ruthless billionaire to find legendary Confederate gold hidden by the KGC, which is supposedly tied to the "Lost Order" – a reference to both Confederate military plans lost during the Civil War and potentially a lost KGC document revealing the gold's location and a broader, sinister plot.
   • Key Elements: Knights of the Golden Circle, Confederate gold, Civil War history, secret societies, historical documents, treasure hunting, political intrigue, Malone's signature blend of history and suspense.

2. The Historical "Lost Order" (Battle of Antietam):

   • What it was: A set of three copies of Confederate General Robert E. Lee's Special Orders, No. 191, detailing his plans for the Maryland Campaign during the American Civil War in September 1862.
   • Why it's "Lost": Lee had issued these orders dividing his army for the campaign. One copy was accidentally dropped by a Confederate courier near Frederick, Maryland, wrapped around three cigars. It was found by Union soldiers from the 27th Indiana Infantry.
   • Significance: This was arguably the most significant intelligence coup of the Civil War. Union General George McClellan learned Lee's detailed plan – that his army was split into four parts moving through Maryland and Harper's Ferry. McClellan famously delayed, saying, "Here is a paper with which if I cannot whip Bobby Lee, I will be willing to go home." He moved cautiously, giving Lee time to concentrate his forces.
   • The Battle: The Battle of Antietam (Sharpsburg) on September 17, 1862, resulted. While McClellan failed to destroy Lee's army, the battle was tactically inconclusive but strategically a Union victory because it halted Lee's first invasion of the North, gave Lincoln the opportunity to issue the Emancipation Proclamation, and discouraged European recognition of the Confederacy.
   • Legacy: The "Lost Order" is a pivotal moment in Civil War history, demonstrating the critical importance of intelligence and the fog of war.

Which one are you interested in?

• If you're looking for a thriller novel, it's Steve Berry's book featuring Cotton Malone and the Knights of the Golden Circle.
• If you're interested in Civil War history, it's the famous lost Confederate orders found before the Battle of Antietam.

Let me know if you'd like more details on either!