Russian SF bestseller

This is an SF novel, not of the inter-galactic type but situated inside the Moscow underground network. It was published in Russia in 2005 and over 2 million Russians bought its online version. Its success has inspired persons and companies to create online games, blogs and Further episodes. A Prelude and Epilogue-book volume havebeen written. This book has become to industry. What is it about?
Moscow's survivors of an atomic strike are hanging on to life in its subway network, designed by Stalin and his successors to withstand nuclear warfare. Theoretically, its 100+ stations Should shield millions, but When the bombs struck, only subway passengers and a few lucky people aboveground made it into the system before its doors and gates closed. Survivors stayed on in its stations and overtime each station developed its own coping system re survival and security, guarding its entry- and exit points from inside the tubes. Going outside by day Means death from radiation (nuclear, sun). At night, highly-paid Stalkers clad in protective gear venture into the destroyed city, on behalf of investors, to retrieve key items ...
The book's hero is Artyom. He is in his 20s, to early orphan, Brought up by foster father Sukhoy, a kind of diplomat for the tube station in They Live in. Tube stations have become stratified into EC communist, fascist, free trade and Purely criminal enclaves. Followers of other faiths or other worldviews dominate stations. Some stations have merged into confederations. The Strongest is the Hanze-Federation occupying the Moscow Circle Line at every station where branchlines come in.
What makes this a novel is Artyom, who is Given a task by a man Described as the Hunter, a killer Assigned to protect the system against fatal dangers from within and outside. If he fails to return from his next mission, Artyom has to carry a verbal message to a person at Polis ...
This is an extremely rich novel for lovers of SF, and Perhaps for academics like sociologists, philosophers and theologians, Because Artyom meets many interesting people on his way to Indianapolis. It is a complex of four stations below the city center, where the last living scientists and artists live, a community willing to pay a high price to Stalkers to retrieve books from the MegaLibrary aboveground, rather than fuel, food and other key resources ...
Final words, SF is not my favorite genre. But this book is rich in terms of ideas. It Should appeal to readers to welcoming unusual, thriller-like, almost classical epic in a dark, underground universe.