The «Jazz in Willisau» concerts have been publicised and popularised since 1966 by posters that are designed in person by the graphic artist Niklaus Troxler, who is also the founder and organiser of the concert series. Each of these individually designed posters refers, with a versatility that could hardly be bettered, to the music, the style or the performers of the individual concert. Over the years a series of posters has been created that reflects the development both of jazz and of graphic design. The «Jazz in Willisau» posters are highly regarded worldwide, and are to be found in all significant design and poster collections.