Systematic desensitization is a type of behavior therapy used to treat phobias and anxieties. It involves three steps: 1) creating a hierarchy of anxiety-inducing stimuli from least to most severe, 2) teaching relaxation techniques, and 3) gradually exposing the individual to items on the hierarchy while using relaxation to reduce anxiety until all items can be encountered without fear. Developed by Joseph Wolpe in the 1950s, it was widely used but has declined as other therapies have increased in popularity since the 1970s.