Preface: “Quarks-2016”, 19th International Seminar on High Energy Physics Vladimir Andrianov, Victor Matveev, Valery Rubakov, Alexander Andrianov, Maxim Fitkevich, Ivan Kharuk, Victor Kim and Sergei Kolevatov EPJ Web Conf., 125 (2016) 00001 Published online: 28 October 2016 DOI: 10.1051/epjconf/201612500001