Fluent Forever, by Gabriel Wyner

Gabriel Wyner proposes a method for learning languages that he developed for his profesional needs. Besides language learning, this book is great as a guide for training your memory and for that alone it's worth your time.

The book is structured around how to become efficient at remembering things, making memories more memorable by associating structure, sound, concept and establishing a personal connection. The author is a huge proponent of spaced repetition for learning vocabulary and language constructs, specifically using an app like Anki or similar. The book explains the importance of developing good pronounciation habits from the start, which are key for learning any language. The three main challenges for gaining these habits are ear training, mouth training, and eye training.

The only thing that annoyed me about the book is frequent reference to resources available on his website, which have been removed in favor of a paid application. For example, the author explains the importance of a good list of initial words for the language you want to learn, and advices you to download one from his website... only that you can't find the list anymore. I don't think the free resources would have gone against paying for the app.