There are a few key ideas at work here that allow this design to work well not only as an easily identifiable logo for marketing purposes, but more importantly, as a graphic image for your book cover. First, the overall design aesthetic is clean and light, evoking feelings of innovation and intelligence (think Apple). The most successful book covers strike the right balance between image and text. Here, a simple typographic solution that uses a sleek, modern font is combined with a large green button on a white background, allowing this design to be visually engaging, yet also very approachable. The word "RICH" is highlighted at the top in green which is important in terms of having a strong shelf presence since we tend to read only the upper half of book covers when scanning shelves. One additional feature I would recommend would be to emboss (or raise up) the button for added visual effect and to entice onlookers to actually hold the book in their hands (i.e. feel the button).