This delightful little book (less than 100pp of widely spaced text and many figures) discusses Venn diagrams. Now, for those who think a Venn diagram is two or three overlapping circles, it might not be clear how that can fill a whole book. But here we have the history, the author's generalisation to any number of intersecting sets via stereographic projection, their relationships to Gray and binary codes, rotationally symmetric solutions, and maximal planar subgraphs of the hypercube. A fun quick read, and nicely written. And who can resist an author who says: