Black spies

This is an interesting but not deep article on .... well, just read the title:

Black Dispatches: Black American Contributions to Union Intelligence During the Civil War

Some tidbits I found irresistible: Butler's "Big Bethel" offensive was a pre-emptive strike incited by intelligence and reconnaissance; Pinkerton relied heavily on one John Scobell for order of battle information, troop movements, and morale evaluations; AoP intelligence gathering shut down abruptly in November of 1862 with McClellan's relief. (Not that it stayed inactive.)