The "Metro Series" is a popular series of post-apocalyptic novels written by Dmitry Glukhovsky. Set in the underground tunnels of the Moscow Metro, the story follows survivors who navigate a world devastated by nuclear war. The series explores themes of survival, humanity, and the consequences of war. The first book, titled "Metro 2033," was published in 2005 and has since inspired video games, graphic novels, and a film adaptation. The series has expanded to include sequels like "Metro 2034" and "Metro 2035," further delving into the lives of characters as they face both external threats and internal struggles in their harsh environment.