"Fear" is a set of four songs by the band Rush. The composition consists of Part I: "The Enemy Within" (from 1984's Grace Under Pressure), Part II: "The Weapon" (from 1982's Signals), Part III: "Witch Hunt" (from 1981's Moving Pictures) and Part IV: "Freeze" (from 2002's Vapor Trails). Parts I, II, and III were released in reverse order, while Part IV was released a little more than 18 years after Part I. The songs do not follow a set storyline. Instead, they deal with topics relating to the emotion of fear.

Rush performed the first three songs of the tetralogy in their entirety live on the Grace Under Pressure Tour of 1984 as well as the Power Windows Warm-Up Tour of 1985. "Freeze" has never been performed live, and of the other three songs only "Witch Hunt" has been performed live since 1986, being played on the Snakes & Arrows Tour in 2007-08 and the Time Machine Tour in 2010-11, on which Moving Pictures was played live in its entirety for the first time.

In a 1994 interview, Neil Peart describes what inspired the "Fear" Series:

The idea for the trilogy was suggested by an older man telling that he didn't think life was ruled by love, or reason, or money, or the pursuit of happiness -- but by fear. This smart-but-cynical guy's position was that most people's actions are motivated by fear of being hungry, fear of being hurt, fear of being alone, fear of being robbed, etc., and that people don't make choices based on hope that something good will happen, but in fear that something bad will happen.

I reacted to this the way all of us tend to react to generalities: 'Well, I'm not like that!' But then I started thinking about it more, watching the way people around me behaved, and I soon realized that there was something to this viewpoint, So I sketched out the three 'theatres of fear,' as I saw them: how fear works inside us ("The Enemy Within"), how fear is used against us ("The Weapon"), and how fear feeds the mob mentality ("Witch Hunt").

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