Computer hacking involves gaining unauthorized access to computer systems or networks. The document discusses the history of computer hacking beginning in 1960 at MIT and its evolution with personal computers and telephone systems. It describes different types of computer hackers including white hats who test security systems for non-malicious purposes, grey hats whose activities go beyond this, and black hats/crackers who hack with malicious intent. Major computer crimes are outlined like those committed by Adrian Lamo in 2003 and Kevin Mitnick in the 1970s-80s. Ethical issues around hacking are also addressed.