The start couldn't be worse. I just finished Metaprogramming in .NET, unwrapped the plastic sheet from this one to read just in the first chapter "The online version of this chapter (doi:10.​1007/​978-1-4842-2111-2_​1) contains supplementary material, which is available to authorized users." Nice... really nice, so I bought a book but I am not entitled to "supplementary material" because it is only for "authorized" users. And why bother with the link, you can always drop DOI or any other cryptic ID, and the reader has to figure it out how to access it.For the record, I tried to check it, it seems there is nothing there. There are source codes for chapter 2 and 3.After such intro it is hard to beat the first impression -- you rather find out all the issues no matter how tiny. But with this book it was not even hard to see what the author and publisher are doing -- it is small format (check the size by yourself), it has huge screenshots laid out in such way that for example half of the page 127 is literally empty because the screenshot from 128 (completely trivial, and zoomed in on purpose) is just a hair bigger than empty space. So when you see this book is 158 pages long it is not really true, it is just a trick. Make it rather 120 pages and only then compare it to the price.Minor issues -- when you print some web page you will probably get a header on every page with a link of that page. In similar manner every first page of the chapter includes (c), author, DOI, title of the book. Meh, front page was not enough obviously.Last thing -- there are some amount of surprising typos (how can they made into the code?) but fortunately they are obvious.Ok, but what about the content? There is little substance (don't get in the wrong way, it couldn't be more realistically), the book feels more like additional chapter or two for Metaprogramming in .NET (and it is a pity we didn't get simply second edition of it), but it is to point, it is interesting and... inspiring (!). I just got a new ideas while I was reading it, so you can hardly expect more from a book, right? The last chapter "Future of compiler API" despite it is a bit speculative is really solid, however the example with "Dispose" is so... weird. Author should really change the "vehicle" for the example -- not introduce some twisted new rules for "Dispose" which are against C# guidelines ("If an object's Dispose method is called more than once, the object must ignore all calls after the first one.").I almost truly enjoyed it, same way I almost enjoyed sweet cookie with grain of sand. Shame the author and publisher instead of being 100% fair, played some tricks to fool potential readers. Was it really worth it?