“Professor Fortran Encyclopedia” is a popular science encyclopedia in pictures for children, a continuation of the book “And I was in Computer City.” For children of primary school age. The book takes place in the city of Simplex (Computer Country), where Professor Fortran and his friends live and work, and where new and very important information about computers appears every day. They always need to be entered into the Encyclopedia, which is what Professor Fortran does. It is known about the professor himself that he is a world-famous scientist, as he attends scientific congresses. The professor is convinced that new knowledge must be acquired slowly, having first been thoroughly prepared, otherwise all the new information risks getting confused in the head. In this case, you need not only to read, but also to understand what is written. The professor himself is very neat, and does not like it when pages are broken, for this he prepared bookmarks for all young readers. He often models computer algorithms with his friends. The life of his apartment is quite simple and unpretentious, as evidenced by the situation in the kitchen, and the fact that the professor and X peel the potatoes themselves. Cat X is a supporter of labor automation and a fan of country holidays, fishing and mushroom picking. The educational certification system in Computer Country is not known for certain, but Professor Fortran is authorized to award an honorary diploma to everyone who carefully reads the Encyclopedia. It is worth noting that in addition to explaining the basics, the book contains advice on how to behave in a given situation, for example, when the system is infected with computer viruses. All these incidents happen to the characters when the professor is away on business.