Taj Haider, SI (Urdu: تاج حيدر; born 8 March 1942) is a notable left-wing statesman, nationalist, playwright, mathematician, versatile scholar, and Marxist intellectual. He one of the founding members of Pakistan Peoples Party (PPP) and has been the general-secretary of the PPP since 2010.A mathematician and scientist by profession, Haider provided a vital leadership in the formative years of clandestine atomic bomb projects in the 1970s.