The field guide itself deserves a 5 star rating, but the kindle edition only deserves a 3 star rating. So I split the difference. An field guide from the University of California Press is worth a 5 star rating, but only if it is a print edition or a fully functional electronic edition. I use the Kindle app on my android tablet and kindle field guides just aren't fully functional. If you want to expand a photo or picture of a mushroom (or any graphic) for closer examination, it can be done, but it is an extremely clumsy process. The only electronic version of a field guide worse than a kindle are in the Nook format (you can't zoom in on any graphic). Electronic field guides have the advantage you can carry a lot of them on a tablet computer, saving a lot of weight in the field. Unfortunately, that advantage is sometimes counterbalanced by the fact that you can't quickly scan through the pages to easily find something and the fact that the number of pages increases substantially in digital editions. If you want to buy a digital field guide, I would recommend either buying it as an adobe digital edition (the format that UC Press sells the field guide in) or checking the google (or possibly the iPad edition...I haven't tried the iPad product yet). In the google and adobe editions, a quick gesture instantly expands the graphic and a second gesture returns it to the original size. In the kindle, you can keep on expanding the size of the text, but the graphic stays the same size. Perhaps I've missed some kind of gesture to expand just the graphic, but then, there is absolutely no documentation that comes with the kindle app, so you are left to experiment for yourself. Another warning about kindle books is if you buy magazines (particularly literary magazines), there is no way to bookmark a page, so you can easily come back to it later. You can bookmark regular books, but not periodical publications. In addition, the kindle app leaves books on you device as long as you want to, but it automatically removes older issues of periodicals (limit of 7). The decision to remove a book or periodical should be left up to the reader who purchased it.