Books That I Find Sad

• Judea Pearl (1988). Probabilistic Reasoning in Intelligent Systems: Networks of Plausible Inference. Judea is the father of Danny Pearl, the Wall Street Journal reporter who was kidnapped in Pakistan and beheaded on YouTube.
• Philippe Petit (2002). To Reach the Clouds: My High Wire Walk Between the Twin Towers. Petit performed an illegal tightrope walk between the twin towers of the World Trade Center when they were still under construction. Of course, they are gone now.
• Gary Kasparov (2003). On My Great Predecessors, Part 1. As I understand it, his childhood home in Azerbaijan was destroyed in the post-Soviet war with Armenia. At the time, I tried to follow his two tournaments with the Deep Blue computer, both played on top of one of the towers at the World Trade Center.
• Lawrence Lessig (2004). Free Culture: How Big Media Uses Technology and the Law to Lock Down Culture and Control Creativity. Everything he writes will now always remind me of Aaron Swartz.

These days, neither mathematics, nor clowning, nor games seem to be reliable escapism.