Full disclosure department: The good folks over at Packt Publishing provided me with a review copy of this eBook, on the condition that I review it on my blog and mention it on Twitter and stuff. So here goes!
This book was relevant to my interests since I work a fair bit with Leaflet, and one of the things I do at work is train others to use Leaflet. In fact, two weeks ago I held a small workshop at my job where I went through the basics of Leaflet use, and I thought it would be interesting to see how much the things I talked about overlap with the things in this book. I have not tried running the sample code to verify that there are no bugs in it.
The stated mission of the book is to provide simple, step-by-step instructions for setting up a web map for those with little to no previous experience. I think it does a quite good job of this, and it spends a fair bit of text explaining what exactly the code it asks you to copy does, line by line. Furthermore, it does no try to hide the fact that Leaflet has excellent API documentation and often links there to explain details. (Which I approve of!) It covers all the basic things one might expect, and even one thing I didn’t cover in my intro to Leaflet, which is adapting to mobile and using location APIs. Each chapter builds on the previous, essentially starting with a super simple map and building it out to a relatively complex and useful one.
The last chapter is a bit odd in that it suddenly ratchets up the difficulty a bunch of notches, going from dead simple to an actually rather complex task. (The “Advanced” chapter on designing interactive choropleth maps.) It does a decent job of explaining that as well, and works as a cookbook recipe, but I feel the book might have benefited from another intermediate step before building something that complex.
All in all, I have to say that as an experienced Leaflet user I didn’t really learn anything new from this book, but I can appreciate the structure and relevancy of the examples. For someone who is completely new to Leaflet (and web maps in general) this would serve as a useful condensed guide. On the other hand, all this information can really be gleaned from existing tutorials online. Therefore, I would say that is up to the buyer to decide if spending 4£ on the eBook to save a few hours of surfing about is worthwhile for them. If I was researching Leaflet as part of a job with a salary anywhere north of 4£ an hour and needed info quickly, it would probably be quite easy to justify. Buying the printed version from Amazon (at 13£) would be a waste of time and money, and is indeed probably not how this book is primarily intended to be consumed.