Right under the brand name Lucky Strike, it says "it's toasted." Any idea what that means?
As this excellent advertising poster from 1917 explains, Lucky Strike tobacco is toasted to hold its flavour - as opposed to the sun-drying method, which supposedly doesn't allow the tobacco to retain its flavour so well. As to exactly what the toasting process consists of, I have no idea, and as far as I can tell it's a closely-guarded secret!
A little more information about the slogan "It's toasted" as an advertising campaign can be found here.