The purpose of this study is threefold. Firstly, it provides insight into Shaikh Taqi id-Din an-Nabhani, a Palestinian Sunni Muslim jurist and a radical political activist.Secondly, as the founder and chief ideologue of the Liberation Party, the study explores an-Nabhani''s political ideas and doctrinal tenets. Thirdly, the book examines and discusses the legacy of an-Nabhani,as represented by his prolific political and ideological writings and the continued existence of the radical Liberation Party. Of an-Nabhani''s many works, two have been selected for translation and analysis: Al-Khilafah [The Khilafah or the Caliphate] and Nida ''un Harun ila al-Muslimin min Hizb ut-Tahrir [A Passionate Appeal to the Muslims from the Liberation Party]. These two documents provide both an essential basis for understanding the political ideology and radical programme of action espoused by an-Nabhani and his anti-democratic and non-violent organisation, as well as a useful backdrop for the study of contemporary radical Islamist thought and practice.