Jens Otto Harry Jespersen was a Danish linguist who worked in foreign-language pedagogy, historical phonetics, and other areas, but is best known for his description of the grammar of the English language.
Jespersen was a professor of English at the University of Copenhagen from 1893 to his retirement in 1925. Jespersen was Dean of the Faculty of Arts from November 1904 to November 1906; and Rector (vice-chancellor, or president) of the university from November 1920 to November 1921.
It's amazing when you find out that some things you have discovered for yourself only recently have been seen by people such a long time ago. Interesting read.
Around 500 pages yet this not was not a drawback for me to finish it in around 24 hours. Sure this is only a first reading and I will be back for a more thorough and exact reading later. We are dealing with one of the very first works upon which functional linguistics was developed, yet the book can be used as a very good introduction to linguistics for any student whether advanced or beginner. I rate it very highly.