This book is a Black repertoire against the Ruy López. We will be focusing on the Arkhangelsk (Möller) Defence. In the modern world where computers keep getting stronger and stronger, openings need to be updated on a daily basis. After the emergence of NNUE engines, the style of play has changed drastically. Players started to sacrifice material for long term compensation/initiative trying to pose as many practical problems as possible so that it becomes difficult for opponents to solve all the problems over-the-board in the given time control.