Writing a textbook is inherently egotistical. Either: 1. You think you can explain well-known material better than everyone who tried before 2. Your field rec

Writing a textbook is inherently egotistical. Either: 1. You think you can explain well-known material better than everyone who tried before 2. Your field recently exploded, and you feel that you are the contributor most suited to converting the papers into a book 3. Your field is solitary and obscure, but you think your papers need to be collected into a book I like textbooks! They generally put in effort to unify the notation and find connections between papers, making it easier to learn the topic. I'm glad some people are egotistical enough to write them.