Bundestag President Norbert Lammert and Turkish-German lawyer Seyran Ates introduce the book Verfassung, Patriotismus, Leitkultur – Was Unsere Gesellschaft Zusammenhält (Constitution, Patriotism, Leitkultur – What Holds Our Society Together) on August 29, 2006, in Berlin. Edited by Lammert, the book consists of 42 essays by prominent figures from the fields of politics, economics, science, the media, and culture. Contributors include Chancellor Angela Merkel, director Wim Wenders, and singer and songwriter Wolf Biermann. The essays grapple with the meaning of the terms constitution, patriotism, and Leitkultur [lead culture], all of which are sensitive topics for Germans. The term Leitkultur was particularly problematic. In October 2000, CDU politician Friedrich Merz had used it in connection with the debate on changing the immigration law. In doing so, he sparked an emotional debate about whether the term merely denotes loyalty to the constitution or also entails conforming to German cultural customs such as putting up Christmas trees.