I am a computer scientist who has been a self-directed investor since 1999. In that time I have handily beaten the market despite the dot com crash, the housing crash, and the crash of 2008/2009. I believe investing is part science, part art. I would call myself something of a contrarian investor. Knowing when to buy and when to sell are judgement calls. Hopefully as time moves on and I gain more experience, my judgement improves. I trust nobody more than myself to make those calls.