Electrical conduction in conventional metals can be modelled by considering a 'fluid' of electons whose mutual interactions manifest in renormalized properties such as an enhanced effective mass. In the low temperature limit, the resistivity of a metal is expected to be quadratic in temperature. 'Strange' metals, by contrast, exhibit a linear resistivity down to lowest temperatures. It is itself difficult to explain, but it is perhaps more intriguing that strange metals are often hosts to high temperature superconductivity. The connection, if any, has yet to be explained, but it is widely assumed that cracking high temperature superconductivity will require understanding the strange metallic state from which it is often derived.