There is a lot of rumble out in the CW community regarding a new book on the market. The CW way of life written by Chris Rutkowski NW6V. I am only a quarter of the way into it but this book is for anyone who is anywhere in their CW journey. In the few pages, I have learned about Samual Morse what he did and did not do for morse code and others named Alfred Vail and Friedrich Gerke who moved code along its journey.
Once past a short history lesson you read and learn about how code is linked to harmonics, and rhythm and step back and see the method. Other topics are moving from counting dits and Dahs, code speed blocks, habits for code learning and so on.
This book is worth a look and can be done here for your kindle the book is also available as a good old page-turning book on Amazon as well.