The short-sighted adolescent is a passionate reader who takes various cultural figures as models, trying to emulate both their lives or their works. The pupil protagonist is a poor student, who likes science and reads a lot of books, sometimes staying up all night to do so. At the age of 15, he decides to write a novel to demonstrate to his teachers that he is not as mediocre as all the other students, and is prepared to give up everything he holds dear for his art! The novel is written in a number of notebooks – the diary of the title – but our myopic hero ultimately fails in 3 subjects and is too lazy to learn and has to repeat the school year.