71 people were killed in one of Europe's worst peacetime air accidents. The report comes the the conclusion that human error was the main cause. The TCAS system (PDF) which should have prevented the collision worked, but the Tupolew crew followed the ATC instructions. It turned out that the air traffic controller missed a key warning on his radar screen in one of a chain of errors. ATCs from nearby airports realized what was going on but weren't able to contact the responsible Skyguide controller because the telephone network did not work: the main telephone line was switched off because of work being done on the telephone network, and the collision warning system was temporarily shut down for maintenance.
The ATC in charge was stabbed to death in February 2004 by a Russian man who lost his wife, son and daughter in the plane crash.
Chapter 1 of "Inmates Are Running the Asylum" by Alan Cooper (American Crash in Cali, Colombia).... Bruce Tognazzini on Interfaces that Kill (John Denver).... The Lessons of ValuJet 592 by the masterful William Langweische.... The same Mr. Langweische has a book called "Inside the Sky: Meditations on Flight" which looks interesting.