Merriam-Webster defines prelude as an “introductory performance or event” and declares that, if musical, it introduces the main theme. The definition gives the first organ solo played at the beginning of a church service as an example. [Apologies for the M-W bias that excludes pianists and modern keyboardists]
A prequel is defined as “a literary or dramatic work whose story precedes that of an earlier work” (The Merriam-Webster Dictionary). Authors without a prelude grab for a prequel with the fervency as riders on a carousel reaching for the coveted brass ring. Didn’t catch it the first time? Grab again during the next go-round.
“Story precedes” are the key words for prequel. No matter when it’s written, a prequel is published after one or more novels in a series. The purpose of a prequel is to bring an Aha! moment, a sigh, or simply a nod of understanding to the reader who questioned the character’s motives or movements in the original novels.
The words for a prequel entice me like the aroma of cinnamon and brown sugar wafting from simmering apple butter in my kitchen. They tempt me to abandon the main course of my unpublished mystery and write a mixed prelude-prequel. I have plenty of material for another trip on the carousel. It’s the text my critique partners cut from my suspense novel and defined as backstory.