Author and screenwriter Lisa Morton delves into the history of Halloween, tracing its journey from ancient Celtic rituals to modern-day traditions.

Halloween today is all costumes and candy, but it was not always like this. Halloween's origins lie in ancient paganism and religion.

In the U.S., Halloween has become heavily commercialized, with specific traditions that have been exported all over the world.

With roots in both pagan and Christian traditions, Halloween has never stayed the same for long. The holiday's identity has changed so rapidly, even in the past few decades, that a comprehensive, up-to-date study is tricky.

In 2013's Trick or Treat, novelist and Halloween expert Lisa Morton gives readers a historical overview of this spooky festival and explores its recent manifestations.