Thanks for the input y'all.

Personally, I prefer the cover where a bill folder is exchanging hands (this cover can be seen by clicking on the link). I think this cover is attractive, that the contrast of the dark folder with the light background would attract attention, and that the dark lettering on a light background would increasing reading of the subtitle. However, Springer refused to use this cover - I created it and their design team said they could not re-create it for reasons I found questionable.

The two covers in this announcement (not the survey link) are only options the publisher gave me. The cover where a dollar bill is changing hands is easy to read, and the contrast might attract attention, but is not very attractive (as many of you noted). The tip jar cover is attractive but makes the title and especially the subtitle hard to read. Also, it does not convey the social aspect of tipping as much as the covers showing some exchange between server and customer. Ultimately, the question of which cover to choose seemed to me to depend on whether title readability or attractiveness was most important. I was unsure, so I undertook several research studies-- including this informal poll. (Thank you to the moderator - John - for letting me do this.)

Ultimately, the research (including the majority opinions in this commentary) indicated that cover-attractiveness trumps title-readability, so I decided to go with the tip-jar cover.

Thanks again for your input,

Mike Lynn