Stefano, I quickly browsed through the webpage and I would like to know why this book could be appealing to polyglots or linguists alike. They will have already mastered several languages. Your explanations on why this book could be interesting for polyglots and linguists do not really convince me. I guess your book caters more to people who would like to start learning a foreign language (maybe for the first time). I don't really see, where the benefit is compared to other books and tips sold by other language learning professionals. There are also already many websites about how to learn languages (like "Hacking Chinese"), which I personally find more interesting than the Benny Lewis style.

Coming back to the term "polyglot". If a polyglot still needs general tips on how to learn languages, then I doubt he is a "real" polyglot". I don't like that in the internet the bar is set so low when it comes to polyglots and so many people who can just have basic conversation in a couple of languages already call themselves polyglots. It just seems to be a fashionable term nowadays. I've already learnt several languages (but don't consider myself polyglot), so I honestly don't feel tempted to by the book, because I already know how to learn languages.

So, is your book more aimed to beginners (from monolingual environments) or is there a real selling point for the experienced language learner?

Hi Stefano, I agree with Miriam's comments. Your book would appeal more to inexperienced language learners. Polyglots may pick up a few tips, but for the most part, true polyglots would have already fine-tuned their own learning methods. 

As a language learner, I'd be more interested in the practical tips that you provide as opposed to your personal experiences. That being said, I wouldn't necessarily purchase the book as I already have learned a few languages and know what methods work best for me. However, I can see its appeal to English speakers who have never studied a second language in depth.

One thing to consider is what your book offers versus other books (like Benny Lewis) and the tons of free advice available from polyglots on the web. There is already a lot of material out there based on what you describe (e.g., learn, don't study; immerse yourself as much as possible), so consider what would make your book stand out. 

Good luck!

Yeah, what am I? ;-) I would consider myself more an experienced than a casual learner. I learnt five languages at school (three obligatory and two voluntarily) and only two of them I can not speak, because I don't consider it important to me to be able to speak Latin and Ancient Greek. ;-) I have lived abroad in several countries, taught German for many years, and learnt about linguistics, but I am not and don't work as a linguist. I already read a lot about language learning tools and some of them I tried myself or suggested to my students. So I am not on the lookout for more tools. Actually you already lost me at "Benny Lewis". I know he is an inspiration for many language learners, but he is just not my cup of tea.

I don't call myself polyglot, because I am far from being one. Maybe "language enthusiast" is a more fitting term for me (see also the discussion of this term here: http://www.languagesurfer.com/2013/10/21/the-defintion-of-polyglot-and-why-im-not-one/. I find that quite interesting.)

I'm sure that there is a market for your book. It's just that not every language learner falls into your categories.