I really enjoyed this self-help book from 100 years ago for multiple reasons. It's a jolly good read because of the author's style, though I'm biased towards the British style. Also the author have very good insights into how people really work and can express things very clearly.

There were quite a few expressions that I should still look up (the language changed a lot since 1910) and many of the contemporary authors mentioned are unknown to me, but that does not take away from the message.

It is a very short book, one could get it from its Project Gutenberg page, read it, decide what you want to do with it, then you can revisit the Wikipedia summary to revise it any time you feel the need.