The book The Pretty Fly was commissioned and printed by the Main Department of Public Health. It is possible that the task was entrusted to him by the Youth Red Cross, in which Sava Popov was an active member – at that time he wrote articles, participated in assemblies, and contributed to their newspaper Az sluzha (I Serve).

The publication served two concrete goals – to educate children about the role of flies in spread of dangerous diseases and to teach them hygiene habits. At the end of the 1930s, urban culture, with its household improvements, had already entered the lives of many Bulgarians, but the general hygiene of the population was still not at the necessary level. Advertisements in the newspapers of this period proposed efficacious products to combat carriers of contagion. Publications in the press frightened with true stories of disease and death caused by flies. During this period, one notices a lively interest in the world of insects. The rector of the Academy of Arts, Ivan Lazarov, studied the world of ants and compared it with the human world; Jānis Larri’s book The Extraordinary Adventures of Karik and Valya was published, originally conceived as a popular scientific work about insects.

ava Popov looked at the human world through the lens of the fly and constructed the narrative by interweaving existential themes with elements of drama. Three flies live in a dark dustbin beside a restaurant. They regularly receive food, but their lives are filled with banalities. One day, a can of sardines rolls into the garbage. While the two flies feed on the leftovers, the main character is captivated by the exotic picture on the label. That night she has a prophetic dream, and in the morning she tries to convince the others of the urgency of escape: “You are short-sighted! You don’t see the doom we face or that we can live happier lives.” The urge to leave her dark habitat and “to fly in the bright world” saves her life at the last moment. As she flies off with a cry of “I am not afraid!” her two older sisters are buried underneath the next delicious lunch.

The story continues with several twists: amazement at the flies that swarm in the restaurant’s kitchen; the main character’s first encounter with a mirror and her admiration of her own image; a meeting with a fly from the “bright world,” who initiates her in the fly’s life work, namely – infecting people with diseases. Then the action develops like a thriller and ends with a mass death of the flies, defeated by the hygiene inspectors and the sprayers of poison. On her deathbed (a sticky flytrap put out by the health inspector), the Pretty Fly takes stock: “I regret that my descendants have perished so ingloriously, and I die even more ingloriously.” And her old enemy, the Bloodsucking Spider, fallen prisoner beside her, also takes stock in the style of an ancient Greek drama: “They were born, they lived, and they died like flies!…”

The illustrations for the book The Pretty Fly were done by the artist Iliya Petrov; he was at that time 34 years old and a member of the New Artists group. This was an association founded in 1931 by socially oriented young artists with progressive ideas. Iliya Petrov graduated from the academy in Munich, where he mastered the techniques of German satirical drawing, grotesque, and caricature. His passion for drawing animals was also well known – classic sketches from nature, but also those in which the animals took on human features and gestures. In his illustrations for The Pretty Fly, there are no dynamic angles and no realism added by the artist. They literally depict scenes from the book and unfold in one plan. This does not prevent them from being funny and expressive. In the human characters – the doctor and the apprentice – the influence of German expressionism and social graphics from the years between the two world wars can be felt