This book follows up a 2005 International Conference in Yerevan, Armenia dedicated to the 70th anniversary of the 1935 publication of the "green paper", by N.W. Timofeeff-Ressovsky, K. Zimmer and M. Delbruck entitled "On the origin of gene mutations and gene structure". This was the starting point of the NATO Advanced Research Workshop, whose proceedings are published in this book, with papers dealing directly with Timofeeff-Ressovsky’s life, and the "green pamphlet".