Salah al-Bitar was the cofounder, along with Michel Aflaq, of the Ba`th party, later called the Arab Socialist Ba`th Party when it merged with Akram Hourani`s Arab Socialist Party in 1953.
More info:
Here are a couple of good books on Bitar and that heady period of the 1940s and 1950s when the Ba`th party galvanized Syrian and, to a lesser extent, Arab politics:
Kamel Abu Jaber, The Arab Ba`th Socialist Party: History, Ideology, and Organization. Syracuse, NY: Syracuse University Press, 1966; and, Hanna Batatu, Syria`s Peasantry, the Descendants of Its Lesser Rural Notables, and Their Politics. Princeton, NJ: Princeton University Press, 1999.
[from Wikipedia]
Salah ad-Din al-Bitar (Arabic: ???? ????? ???????) (born Damascus 1912, died Paris 21 July 1980), was a Syrian politician who, with Michel Aflaq, founded the Arab Ba`th Party in the early 1940s. During their student days in Paris in the early 1930s, the two worked together to formulate a doctrine that combined aspects of nationalism and socialism. Al-Bitar later served as prime minister in several early Ba`thist governments in Syria, but became alienated from the party as it grew more radical, and in 1966 fled the country. He lived most of the rest of his life in Europe, and remained politically active until he was assassinated by unknown persons in 1980.