This book is the tenth volume in the Discoveries in the Judaean Desert series. It is the first edition, complete with introduction, translation, and commentary, of one of the most important documents found at Qumran: a letter from one of the leaders of the Dead Sea sect (perhaps the "Teacherof Righteousness") to one of the leaders of Israel (perhaps Jonathan Maccabeus). The scroll is a unique and exceptionally interesting legal document from the first century AD, listing a number of important and controversial religious laws concerning the Temple of Jerusalem. According to the scroll,it is the disagreement over these laws that has caused the sect to secede from the rest of the people of Israel. The letter uses the Hebrew term parash, which derives from the same root as the word Pharisees. The letter sheds a considerable amount of new light on the identity and ritual practicesof the sects in the Second Temple Period, as well as helping to establish the antiquity and authenticity of the Rabbinic laws concerning the Temple. The unique language of the document makes it also of prime importance for those interested in the development of the Hebrew language.