Here, in this part of Stockholm that once was the city's absolute centre, some of the streets bustle with tourists from around the world. But if you just turn a corner you can end up in inconspicuous alleyways where the sun seldom shines. At best you might meet someone taking out the trash or who is on their way to work. On an old wooden door is an unremarkable aluminium sign that reads 'Anders Petersen' in punched lettering. It has been there for thirty five years. Obvious marks on the door show that there have been several other signs there too. The door is ajar, as is usual when company is expected. I descend a grey painted, heavy-duty wooden stairway. Here, halfway below street level, it opens out into several small rooms and recesses. The walls are covered with shelving that holds files as well as old photographic-paper boxes marked 'Roxy', 'Elfie', 'Lothar', 'Ramona' and 'Holländske luffaren' while computer monitors sit on workbenches. A man in a black hood sits bent over one of