The religion clauses of the First Amendment provide that "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof..." In modern time the Supreme Court has frequently construed these clauses to create, in Thomas Jefferson's oft-quoted metaphor, "a wall of separation between church and state". This volume summarises the doctrinal debates and shifts on the religion clauses that have occurred on the Court during this period. It summarises and examines as well the legal effect of each of the 56 decisions the court has handed down concerning church and state since 1980.