Lagin is best known for his ever-popular book Starik Hottabych ( , Old Man Hottabych, 1938), a fairy tale telling the story of a genie who is freed from captivity by a Soviet schoolboy. The genie, as is to be expected, has some trouble in adapting to modern life values and technological development. The book was recommended to school libraries by Ministry of general and professional education of Russian Federation; it was made into the film Old Khottabych in 1956.
Lagin's science fiction novels are set in imaginary Western "capitalist" countries and satirize misuse of scientific inventions in bourgeois society. His novella Major Well Andyou ( ? ) is a satiric sequel to H. G. Wells' The War of the Worlds.
Lagin was also a screenplay writer, producing, for instance, the screenplay for the 1967 animation film Passion of Spies.