“You don’t know where your family history will lead until you start climbing the branches,” says John Colletta, a professional genealogist in DC. “Genealogy is detective work. You have to be ingenious, and you have to enjoy the search.”

Some people put family history in book form to pass on to future generations; others write sketches of ancestors. Whatever your goal, Colletta suggests talking to as many relatives as you can and tape-recording the conversations: “Get all the information that’s stored in human memory.” Often, relatives can show you birth and death certificates, diaries, letters, and other documents that confirm or expand memories.

Diane O’Connor, executive director of the Arlington-based National Genealogical Society, says making a family tree is the next step. Write down names as well as birth, marriage, and death dates as you find them. The NGS sells fill-in-the-blank charts at its Web site, ngsgenealogy.org.

Once you have names and some identifying details, there’s a variety of ways to find documentation. The Internet is an obvious source, but make sure you search trustworthy sites; the book Online Roots: How to Discover Your Family’s History and Heritage With the Power of the Internet by Pamela Boyer Porter and Amy Johnson Crow can help.

The NGS Web site also has tips; An­cestry.com, FamilySearch.org, and Genealogy.com provide access to historical records. CyndisList.com has links to resources, organized by country of origin and ethnicity.

One of the world’s best resources is the National Archives (700 Pennsylvania Ave., NW; 202-357-5000). See its Web site, archives.gov/genealogy, to familiarize yourself with its catalog of materials, then head down to the building to view documents.

The National Genealogical Society and specialized groups such as the Jewish Genealogical Society of Greater Washington (jewishgen.org/jgsgw) , the Washington, DC, Italian Genealogy Club (geocities.com/circolomazzei/index.html) , and local chapters of the Afro-American Historical and Genealogical Society (aahgs.org) hold meetings and classes. A Google search can help you find similar groups.

The NGS sells a kit that includes a booklet on how to get started and family trees. A good book for beginners is Genealogy 101: How to Trace Your Family’s History and Heritage by Barbara Renick. The Handybook for Genealogists (available at Genealogical.com) provides addresses of libraries and record repositories, maps, and other information.

—Kim Forrest