The "Fear" Series originally was a series of three songs (later four) that cover the concept of fear. It consists of (in order of release) part three, "Witch Hunt" (Moving Pictures); part two,"The Weapon" (Signals); part one, "The Enemy Within" (Grace Under Pressure); and part four, "Freeze" (Vapor Trails). The first three were released in reverse order
Here they are, in the order from part one through four, (and maybe five if there ever is one).
Part 1: The Enemy Within Edit
Part 1 deals with how people have internal fears that affect their decisions. The "Enemy" possibly refers to the phobias people have to deal with.
From Grace Under Pressure (1984)
Part 2: The Weapon Edit
Part 2 deal with external fears, such as weapons.
From Signals (1982)
Part 3: Witch Hunt Edit
Part 3 deals with how fear can be used to control people. It's title is a reference to the Salem Witch Trials.
From Moving Pictures (1981)
Part 4: Freeze Edit
Part 4 deals with the choices you have to deal with fear (Fight or Flight response), "Some times I freeze... Sometimes I fly...Sometimes I Fight..."
From Vapor Trails (2002)
Part 1 starts suddenly and fades out at the end.
Part 2 starts by fading in and ends by fading out.
Part 3 starts by fading in, and ends suddenly.
Part 4 ("Freeze") was released 18 years after the previously released segment. Because it wasn't part of their original concept, it starts suddenly and ends suddenly.