His European Blues Fest posters, issued over several years in the mid-late '60s were really good.
But many other large-format rock pieces, like for Fleetwood Mac and such, are not memorable, unfortunately.
Kieser was a huge talent, and very influential. Tne Hendrix was his masterwork, in my opinion.
Kieser started doing rock posters around '68 or '69 - he's done some real classic ones, his Hendrix one is probably best known. http://www.gigposters.com/posters.php?poster=59783
I'll be uploading more Kieser posters, jazz and rock, when I get the time.