Targeted cyber attacks against government and commerce have been on-going since at least 2003 and possibly some time before that. These attacks are commonly known as advanced persistent threats (APT). By far the largest sponsor of these attacks is the Chinese state, although other states also carry out attacks. This is not a new problem; it is simply espionage. These attacks are designed to steal information that will fulfil a clear set of requirements set by the attacker and furnish them with political, commercial and security/intelligence information. These requirements are carefully and clearly identified, shared with a number of government departments and constantly updated. There is evidence of worldwide targeting but only a minority of attacks are identified and fewer still made public. This article seeks to educate the reader on what APTs are, how they are different from other IT security threats and what can be done to identify and mitigate them.