A bookmark for a book (but which book?)

I blogged earlier this week about the freebie bookmark I got with my purchase at the local bookshop during the Independent Bookshop Week. Here is its other side, but I am not blogging about the other side. I said in my first post about it that it is a bookmark for summertime. I think it is fitting that I use it on summertime books or, to be more precise, on books which atmosphere, topic, subject matter, what have you, fit this bookmark. And it struck me after publishing my previous post that I don't have that many summer books at the moment, not unread ones anyway, and I fear that I have no book whatsoever set on a beach or anything approaching. So I need to find a book that goes with it. If you have any suggestions, please put them in the Comments section.