Why Don't You Leave? is a historical biographical novel about a mathematician living in the Soviet Union. The protagonist, Andrei Krylov, is a mathematical prodigy, born in Saint Petersburg in Tsarist Russia in 1900. When Andrei is six, his father is sent to Siberia because of his participation in the 1905 Revolution. Andrei lives alone with his mother until her death in 1910. Andrei is adopted by his wealthy uncle, who is a banker in Moscow. At age seventeen, Andrei accompanies his uncle on a business trip to Saint Petersburg, where they witness the mayhem of the February Revolution.
Andrei's uncle flees to France to escape the coming communist revolution. Andrei remains as a student at Moscow State University. He goes on to become a prominent mathematics professor there. He has many interactions with other prominent mathematicians, both Soviet and foreign. He marries a poet and novelist, and through her meets many of the literary figures of the Soviet Union.
Andrei makes trips to Germany, France, and Poland, and visits with may prominent mathematicians there.
Some of Andrei's friends, mathematicians and scientists, become victims of Stalin's Great Purge of 1937-38.
Andrei sees the suffering of the Russian people during the Great Patriot War. His mathematical expertise aids in the war effort, especially in the defense of Moscow.
After the war, Andrei visits with prominent mathematicians in the Communist Bloc as well as in the nonaligned nation of India.
As professor at Moscow State University, Andrei supervises the PhD dissertations of 87 students, many of whom go on to become prominent mathematicians both in the Soviet Union and abroad.
The book plays on the tension of mathematicians and scientists living under, and supporting willingly or otherwise, a repressive and brutal totalitarian government. Friends from abroad ask him, ``why don't you leave?''