The book written for the Black repertoire deals with Stonewall, it means opening where against 1.d4, c4 and Nf3 Black plays f5, Nf6, d5, e6, c6. Pisture 2 shows content of the book. GM Nikola Sedlak achieved rating of more than 2600, in 2010 he was a champion of Serbia, at the Tromso 2014 Olympiad he won an individual gold medal for the result on the 4th board. He is also acclaimed as an author - his two-volume work Winning with the Modern London System 1-2 was very succesful. Further information about the book is available at qualitychess.co.uk.