Look for lost and elusive information-you may even help to rewrite history.

Genealogists, like other historians, use a variety of sources. Changing needs and perspectives influence the writing and rewriting of history. One history professor I had claimed that a proper account of a past era could not be published until all the participants were dead. Another asserted that at least 50 years had to elapse after an event before anyone could claim to write an impartial account of what had happened.

One significant factor that leads to new studies of old subjects is the discovery of sources. Documents turn up that had previously been unavailable, or at least unknown-a new diary, a cache of old letters or issues of a defunct newspaper can cast new light on past events. Sometimes they change our understanding of motives or the order in which things occurred, and cause us to reconsider ?the whole story.

Who knows what slants on the past are hidden away in old letters and diaries. What genealogical clues await us in old Bibles, with their family records? Who will recognize ?the importance of an overlooked sheaf of papers?

Perhaps you'll go hiking or fishing far from the road, and find a toppled headstone or a small forgotten burying ground.

Hundreds of fortunate finds await the diligent researcher. Here are a few examples I know about-and you may be aware of others.

In Scotland, genealogist Donald Whyte was digging through the muniments of Lord Melville, and found the passenger list of 70 Scots from Perthshire brought to Pictou, NS, on the Commerce in September 1803. For more than 175 years, this list awaited its reading by someone who knew what it was. While going through the papers of Sir William Young at the Nova Scotia Archives and Records Management, I recognized three pages of the 1827 census of Halifax, believed lost decades before. It seems the clerks in Young's legal office cut up the census pages and used the blank backs as scrap paper. Three survived because they had calculations of money scribbled on them. In this case, money talked.

The 1851 census of Nova Scotia was believed to have perished, with the exception of Hants and Halifax counties. However a few years ago the Pictou County portion was located in a public building in Pictou. (I urge you to search attics.)

Reverend Hugh MacKenzie came from Scotland to work in the Wallace-Earltown Tatamagouche area of Nova Scotia in 1832. When he returned to Ross-shire, Scotland, in 1844, he took his registers with him; 140 years later a researcher discovered four pages of marriages and 34 pages of baptisms from Nova Scotia and PEI among the records of the Parish of Tarbat, in the far north of Scotland. This reminds us that sometimes a clergyman regarded his register as a record of his ministry, rather than as that of the congregation. In addition, churches merged, shut down or divided. If there were records, who took them? The old registers may be where no one has thought to look. Perhaps in the heart of New Brunswick, or in an abandoned outport in Newfoundland, there are yellowing pages slowly turning to dust. We won't know unless and until someone finds them.

Those who conduct cemetery surveys track down forgotten and overgrown tiny burial sites across the region; the markers may contain vital clues for the genealogist and local historian. If old markers have fallen down, a good local heritage project would be to right the stones, both out of respect for those buried there and because they offer information that someone will appreciate knowing. I urge people to seek out the lost and the missing, and to examine poorly identified documents; to see that documents are preserved and their information made available. I invite readers to tell their stories of "finds" they have made, or of which they have knowledge. Above all, try to convince anyone throwing away old records to consider giving them to local museums, libraries or heritage groups. The past in this context is not only possibly related to you, but that of a collective unit: country, region, province, county and community.

Dr. Terrence M. Punch is the author of Erin's Sons: Irish Arrivals in Atlantic Canada 1761-1858, Volume 3 (Genealogical Publishing Company, 2009).