Question 3：あなたは入門書を誰のために書いてるの？ Thank you for introducing your new book. It's clear that many developers here are very interested in it. You characterize your new approach as "depth-first", "concrete-first and "concept-based". To be frank, all those characters do not seem to be easy to understand. Would you give us some more details about them? Your "preface" says that you have a fundamental assump
