1/f noise: a pedagogical review

This is a pedagogical review of the ubiquitous 1/f^\alpha noises. The sections include the representation of 1/f^\alpha noise as a superposition of many relaxation processes; a discussion of the infinitely large fluctuations in the low frequency limit; 1/f^\alpha noise from diffusion processes; the measured statistical properties of 1/f^\alpha noises; 1/f^\alpha noises in self organized criticality; scaling laws in earthquake physics; 1/f noise in deterministic dynamical systems; an example of noise in a biophysical system; the numerical simulation of 1/f^\alpha noise; 1/f noise literature (including online resources).