Marian Spencer’s great-great-grandfather was “quite a scoundrel” — a man who used multiple aliases and even had one of his legs shot off in a confrontation with a sheriff.

“He wasn’t a very nice man,” Spencer said.

Though he wasn’t the most upstanding of relatives, Spencer was thrilled to learn about her great-great-grandfather, and several other of her and her husband’s ancestors, through genealogical sleuthing.

She’s used computers, libraries and the Vashon-Maury Island Heritage Museum as resources to learn about her predecessors and has traced her ancestors back many generations to pioneering families on Vashon.

“You never know what you’re going to find in the closet,” Spencer said. “You have to have an open mind — it’s interesting what you dig up.”

To help guide those new to genealogy, Spencer, a member of the Heritage Association, helped organize an introductory genealogy class that takes place this Saturday.

Renowned genealogist Ed Swan Sr. — the father of Ed Swan Jr., the editor of The Loop — will discuss beginning genealogy, introducing newbies to the joy of ancestral research with demonstrations and tips.

Swan, a charter member of the Olympia Genealogical Society, will introduce attendees to resources on the Internet, at the Heritage Museum and at local libraries, Spencer said.

Genealogical research is a pastime for many on Vashon and elsewhere, Spencer said, and with good reason.

“A lot of people want to know about their past,” she said. “It’s really interesting, and it can be very exciting.”

A free class in genealogy, led by genealogist Ed Swan, takes place from 1 to 3 p.m. Saturday, March 27, at the Gordon Building, located just behind the Heritage Museum at 10105 Bank Road S.W. Call 463-7808 to reserve a space.