[nhecker]

The Art and Skill of Radio Telegraphy by N0HFF[1][2] is also an interesting read, and goes into a lot of the history. I recommend it if you want to know more on the subject.

[1]: https://www.qsl.net/w9aml/documents/TheArtandSkillofRadioTel...

[2]: You can also find it elsewhere; the title is distinctive enough.