I had forgotten Foote's comment on Forrest. And yes Forrest kept the "skeer" on Sherman.
I believe General Lee said of Forrest, ""A man I have never met, General Nathan Bedford Forrest, Accomplished more, with fewer troops than any other officer on either side."
Sherman also said he would give 10,000 lives and the entire Federal Treasury to kill Forrest.
Of course, that was when Sherman was in constant fear that Forrest would cut his line of supplies and force him to abandon his Atlanta campaign. If Forrest had been loosed on Tennessee, rather than ordered to defend Mississippi from Federal raids, the November, 1864 election might have seen a different result.