Leonid Anatolievich Levin, born on November 2, 1948, is a renowned Soviet-American mathematician and computer scientist. He is celebrated for his significant contributions to randomness in computing, algorithmic complexity, and intractability, as well as his work in average-case complexity, foundations of mathematics and computer science, algorithmic probability, theory of computation, and information theory. Levin earned his master's degree at Moscow University, where he studied under the guidance of Andrey Kolmogorov, and completed the Candidate Degree academic requirements in 1972. Notably, he and Stephen Cook independently discovered the existence of NP-complete problems, a groundbreaking theorem that revolutionized computer science and became a basis for one of the seven Millennium Prize Problems. Levin's remarkable achievements have earned him prestigious accolades, including the Knuth Prize in 2012 for his discovery of NP-completeness and the development of average-case complexity. He is a member of the US National Academy of Sciences and a fellow of the American Academy of Arts and Sciences. Currently, Levin serves as a professor of computer science at Boston University, where he has been teaching since 1980.

Leonid Zakharovych Stein (Ukrainian: Леонід Захарович Штейн; November 12, 1934 – July 4, 1973) was a renowned Soviet chess Grandmaster from Ukraine. His exceptional talent and strategic prowess led to three victories in the USSR Chess Championships during the 1960s, cementing his position among the world's top ten players of that era.Stein's remarkable journey began in Kamenets-Podolsky, Ukraine, where he was born and later served in the Soviet Army. He achieved the national Master title for chess at the age of 24 and made his mark in the chess world by winning various championships and tournaments, showcasing his prowess on the international stage.Despite facing challenges in the World title competitions, Stein's legacy as a brilliant attacking genius and a master of sharp openings such as the King's Indian systems and the Grünfeld Defence continues to inspire chess enthusiasts worldwide. Tragically, his life was cut short at the age of 38, leaving behind a lasting impact on the chess community. Stein's creative style and intuitive gameplay continue to influence aspiring chess players, ensuring his enduring legacy in the world of chess.

Leonid Vladimirovich Sherwood, also known as Shervud, was a prominent Russian sculptor of the Modernist period. Born in Moscow to a family of English descent, his father and brother were both architects. Sherwood's notable works include the Makarov Monument, a memorial to Admiral Stepan Makarov, and the Swallow's Nest, a decorative castle in Crimea. He was among the first sculptors involved in monumental Soviet sculpture after the 1917 Revolution and contributed to numerous official busts and statues. Sherwood received his education at the Moscow School of Painting, Sculpture, and Architecture, as well as the Imperial Academy of Arts in St. Petersburg, where he studied under renowned sculptor Vladimir Aleksandrovich Beklemishev. He further honed his skills as a pupil of Rodin in Paris. Sherwood's legacy lives on through his impact on Soviet sculpture and his students, such as Sarra Lebedeva. He passed away in Leningrad at the age of 83.

Leonid Nikolayevich Sobolev (1844–1913) was a prominent Imperial Russian Army general and politician known for his role in the Russo-Turkish War of 1877–78. He advocated for Russian military and foreign policies aimed at expelling the Ottoman Empire from Europe and gaining control of the Bosphorus to secure access to the Mediterranean Sea. Sobolev's influence extended to Bulgaria, where he served as Prime Minister and Minister of the Interior, implementing measures to limit the franchise and reduce the size of the National Assembly, which significantly weakened the Liberal party. His aristocratic manner and attempts to bribe assembly members led to conflicts and ultimately his resignation. Sobolev's tenure was marked by power struggles and political maneuvering, culminating in his resignation and the rise of a new coalition government under the leadership of Dragan Tsankov. Despite his contentious tenure, Sobolev's impact on Russian military and foreign policy remains a significant aspect of his legacy.

Leonid Nikolaevich Stark, also known by his pseudonyms Afghani, L. Manucharov, and P. Ryabovsky, was a prominent figure in Russian history. Born in 1889 to a family with strong military ties, Stark became involved in the revolutionary movement at a young age, joining the Russian Social Democratic Labour Party in 1905. Throughout his life, he faced multiple arrests and exiles due to his revolutionary activities. Stark's contributions to the Bolshevik cause were significant, including his role as deputy People's Commissar of Posts and Telegraphs of the RSFSR and his leadership in the Russian Telegraph Agency (ROSTA).His diplomatic work took him to various countries, serving as the plenipotentiary of the USSR in Afghanistan from 1924 to 1936. Stark played a key role in signing the Soviet-Afghan treaty on neutrality and mutual non-aggression in 1926. However, his career took a tragic turn when he was arrested in 1937 on charges of counter-revolutionary activities and subsequently met a grim fate, likely being shot in November of that year. Despite this, Stark was posthumously rehabilitated after the Khrushchev Thaw.Leonid Stark's life and contributions reflect the tumultuous and complex political landscape of his time, leaving a lasting impact on Russian history.