The Big Picture:

What comes to mind when you think of Halloween? Pumpkins? Witches? Black cats? Five-year-olds in Spiderman masks proffering open shopping bags while their mothers lurk anxiously in the shadows?

Lesley Bannatyne thinks of those things too, but for her, Halloween has a more universal appeal that may have escaped the rest of us, preoccupied as we are with whether we have enough Snickers bars on hand or whether we have been able to costume our children as the latest Disney character.

“There are very few holidays that allow you to be original, creative, and generous all at the same time. There’s no other holiday where people open their doors to strangers. Trick-or-treating may seem like a silly custom, but it goes back to feudal lords sharing their wealth when the weather was starting to get cold and times were tough.”

Bannatyne ought to know. She is one of the nation’s foremost Halloween scholars, the author of two books and numerous articles on the subject. A freelance writer who works as communications director for Harvard’s Music Department, her professional interest in the subject started when she got a contract to write “Halloween: An American Holiday, an American History” (Facts On File Inc., 1990).

“Really, it could have been anything. It could have been a book on the kidneys, but I probably wouldn’t have become a health care writer. Somehow it was the right match as a subject.”

Bannatyne’s research has uncovered the origins of Halloween in the misty Celtic past, in homecoming celebrations where the dead were welcomed along with the living and bonfires were lit on hilltops to propitiate the waning sun. Later the Catholic Church assimilated these pagan rites into the feasts of All Saints and All Souls.

She has discovered many other things, too, which she shares in her first book and in “A Halloween How-To: Costumes, Parties, Decorations, and Destinations” (Pelican, 2001).

Much contemporary Halloween lore is gleaned during her attendance at Halloween Convergence, a convention for Halloween professionals, held in June, with workshops on things like simulating bloodstains and “corpsefying” a plastic skeleton.

Many of these enthusiasts live and breathe Halloween 365 days a year, Bannatyne says. Some can be a little strange, but a nicer bunch of folks you’ll never find. And lots of fun too.

“Where else can you go where, when someone puts on ‘The Time Warp’ [from ‘The Rocky Horror Picture Show’], everybody knows all the steps?”