This book of sources is meant to complement the biography of Gra?mann and the proceedings of the 2009 Gra?mann Bicentennial Conference (Birkh?user 2010). "Roots and Traces" will interest all scholars working on Hermann Gra?mann and related topics. It offers newly discovered pictures of family members, historical texts documenting life in this exceptional family and an English translation of these previously unpublished papers.