You've traced Great-great-grandpa Jonah back to the old country in the 1830s, but there the trail suddenly goes cold. Who are his parents, your third-great-grandparents? You haven't a clue. It's as though Jonah simply materialized out of thin air (or, just like his Biblical namesake, was spat out of a passing whale).

Maybe you've painstakingly documented Great-grandma Edna from one census back to the next, even working around that pesky burned 1890 enumeration. Then she and her whole family mysteriously disappear. They should be in the 1870 Kansas census—but they're not. What happened? Did a Kansas tornado sweep up poor Edna and carry her clan off to Oz?

Sound familiar? It's the genealogist's nightmare: Your patient progress in discovering your family history comes up against the dreaded Brick Wall. Those darned ancestors of yours have pulled a fast one and left you banging your head in frustration. Maybe their records have disappeared, the courthouse has burned or your kin simply aren't where they're supposed to be. Perhaps they are there, but you can't find them in the morass of people with the same last name, or the maiden-name dilemma has stopped you. Or you've reached the point where your ancestors "crossed the pond," only to have their trail sink into the Atlantic.

Don't give up! Your brick-wall problems can be beaten. You just have to learn some tricks for going over and around the roadblocks to your family's past. Some of these "brick-wall busters" borrow from the techniques of professional genealogists. Others—don't tell!—bend the rules a bit. All 31 ideas can help you find new genealogical avenues, so you can resume your research.

Face it: A brick wall won't make a very pretty picture in your family album. So let's start busting.

1. Work sideways with siblings and cousins.
The most obvious way to get to the other side of a brick wall is to go around it. So start by pursuing parallel branches of your family tree: If you know the names of Jonah's brothers and sisters, try searching for their parents, just as if these siblings were your direct line. The parents of your ancestor's siblings, after all, are your ancestors, too. If you don't know of any siblings, cousins offer the next-best clues. Find their parents' names and then work sideways to your ancestor—the brother or sister of Jonah's aunts or uncles. You often can identify potential relatives using marriage records: If somebody with the same last name is listed as a witness to the marriage, odds are he's related.

Still stumped? Cheat a little: See if you can skip a generation, identifying Jonah's grandparents by using what you know about his cousins or aunts and uncles; then maybe you can work forward to the missing link of Jonah's parents.

This sideways approach can be particularly valuable if your brick-wall ancestors were on the move—across America or the Atlantic. Unlike today's far-flung families, people in olden times typically packed up and traveled in groups. For example, my great-grandfather Gustav Magnusson and his brother John left Sweden together in 1876, and both wound up in Moline, Ill. If I couldn't find Gustav back in the old country, I could follow John's much better-documented trail (since one of John's sons left a brief biography of him). In turn, their siblings Johanna and Carl followed in 1879. So a genealogist among Johanna's descendants could beat her brick wall by working sideways through Carl.

2. Follow the cluster.
You don't even need siblings or cousins to try a sideways detour. Consider employing what Emily Anne Croom, author of the best-selling genealogy guide Unpuzzling Your Past (Betterway Books, $18.99), calls "cluster genealogy." It's not just immediate family who migrated together way back when: In-laws and neighbors pursued the same paths, as well. The fellow who ran the grocery store next door to your family, or who owned the adjacent farm, probably moved there from the same place as your ancestors at about the same time. You can use city directories (more about them later) and land records to find your ancestors' neighbors in place A and to search for the same folks in previous place B—where your family, too, may have originated. The Bureau of Land Management's General Land Office Records Web site is a gold mine of records for states in the former Northwest Territory, the "old southwest" of the frontier South, plus Florida and Missouri.

3. Find fellow travelers.
The cluster approach also works on immigration brick walls. If Great-great-grandpa's trail dead-ends at the ocean's edge, look for his friends and neighbors in passenger lists. You might find his name—horribly mangled by some ship's clerk—on the same page. Still no luck? Find out where the people in his cluster came from, and search for him in the same parish or town. In researching my ancestor Gustav, I found that so many people—most unrelated to me—had come to Moline from his same parish in Sweden that the Swedish-American Genealogist published an article about it.