I felt that way too -- I barely knew what the battle of 2nd Manassas was -- just a brief interlude between the Peninsular campaign and Lee moving north.
When I read about the battle, I got intrigued by the controversy about the Union general, John Pope. Most accounts blame him unstintingly but Kenneth Williams' excellent Lincoln Finds a General shows that many of his decisions were either correct or quite reasonable given the information available to him.
What I like about Pope is that, unlike McClellan, he is an aggressive general. In fact, Halleck had to keep restraining him as the Union army in the West crept toward Corinth. If McClellan had learned that Jackson was in his rear, his only thought would have been retreat.
Pope's reaction was the opposite: the Confederate army is divided -- let's defeat Jackson before they can reunite. His inability to find Jackson was not really his fault, the result not only of conflicting intelligence but Jackson's own errant route.
Meanwhile, McClellan withheld reinforcements, and even supplies, Pope had been promised and based plans on.
At some point, Pope did sorta fall apart and for that he is rightly faulted. But, a new general from the West some of whose corps commanders wanted him to fail (and a motley crew they were), coping with Lee's most dramatic maneuver, who wouldn't get shaky legs. Well, we all know the answer -- Grant.
Why??? 
