Charles Sanders Peirce was an American scientist, mathematician, logician, and philosopher who is sometimes known as "the father of pragmatism". According to philosopher Paul Weiss, Peirce was "the most original and versatile of America's philosophers and America's greatest logician". Bertrand Russell wrote "he was one of the most original minds of the later nineteenth century and certainly the greatest American thinker ever".

Charles Sangster was a Canadian poet. He was the first poet to write poetry which was substantially about Canadian subjects. The Dictionary of Canadian Biography calls him "the best of the pre-confederation poets."

Charles Sears Baldwin was an American scholar and professor of rhetoric at Yale University. Born in New York City in 1867, Baldwin entered Columbia College at seventeen and received his A.B. in 1888. He was one of the earliest students to be granted the Ph.D. degree in English at Columbia. Besides teaching at Yale (1895–1911), Baldwin also worked at Barnard College and Columbia University. He was married twice, first in 1894 to Agnes Irwin, and then to Gratia Eaton Whited in 1902. Most of his life an Episcopalian, he converted to Catholicism the year before his death. Baldwin died in New York City in 1935.

Charles Seignobos was a French scholar of historiography and an historian who specialized in the history of the French Third Republic, and was a member of the Human Rights League.

Charles Seymour was an American academic, historian and the 15th President of Yale University from 1937 to 1951. As an academic administrator, he was instrumental in establishing Yale's residential college system. His writing focused on the diplomatic history of World War I.

Charles Haddon Spurgeon was an English Particular Baptist preacher.

Charles Stuart Calverley was an English poet and wit. He was the literary father of what has been called "the university school of humour".

Charles Sumner was an American lawyer, politician, and statesman who represented Massachusetts in the United States Senate from 1851 until his death in 1874. Before and during the American Civil War, he was a leading American advocate for the restriction and abolition of slavery. He chaired the Senate Foreign Relations Committee from 1861 to 1871, until he lost this position over a dispute with President Ulysses S. Grant over the attempted annexation of Santo Domingo. After breaking with the Grant administration, he joined the dissident faction of Liberal Republicans. He spent his final two years in the Senate alienated and isolated from his party until his death in 1874. Sumner had a controversial and divisive legacy for many years after his death, but in recent decades, his historical reputation has improved in recognition of his early support for racial equality.

Charles Timothy Brooks was a noted American translator of German works, a poet, a transcendentalist and a Unitarian pastor.

Alfred Charles Tomlinson, CBE was an English poet, translator, academic, and illustrator. He was born in Penkhull, and grew up in Basford, Stoke-on-Trent, Staffordshire.