Will Eisner was the most influential comics creator... period. With all due respect to remarkably talented men like Kirby, Cole, Siegel and Shuster, Lee, Barks and all the rest.
Eisner saw not only the artistic potential of comics but the commercial and instructional potential as well. With that in mind he created American Visuals Corporation and PS Magazine (featuring the beloved Connie Rodd).
Now the good people at Digital Comics Museum have downloaded a whole truckload. You can see that Eisner had put a lot of thought into the problem of teaching through sequential art. You'll also notice he has pretty much solved the problem of holding soldiers' attention while instructing them.