BMD....Birth, Marriage, Death. Records created at the time of the event by an eyewitness to the event. Finally! A primary source. Still not perfect. Still open to someone else's interpretation and still an opportunity for error. My own child, born in 1987, has a corrected copy of her original birth certificate. I filled out the form very carefully, sent it in and received the certified birth certificate with her middle name spelled wrong. I filled out a correction form and sent it in and received back, the very same birth certificate with the wrong spelling crossed out and the correct spelling written in on top! Whatever.
The vital records are what we need to finally verify all those dates and places and relationships that we've heard about through family stories, census records and compiled histories. Usually you can order these records from the courthouse in the county where the event occured. There is a fee, but if you just need a photocopy for research purposes, that fee is small. Just this week, I sent off for the death certificates of my four maternal great grandparents. Each copy was only .50 and I sent a SASE with two stamps, just to be on the safe side. Pretty cheap, in my book. I'm like a kid at Christmas, waiting for them to come back.
To find out where to send for the records, you have to know the county where the event occured. In my case that was pretty easy to figure out. Since I'm conducting my research backward; starting with the death of the individuals, I used several different search techniques online to find where they were buried. The easiest thing to try is to type in the person's name and the word cemetery. ie John August Borgreen Cemetery. Hit enter and see what pops up. When I did this, I got several relatives at once. I clicked on that site and continued entering more names to see who else I could find. I found all the great grandparents buried in two cemeteries in the same county. My lucky day! After you find where they are buried, go to the website for that county and download the forms you'll need to fill out and send in for the records. Don't send too many forms at once. Make it easy on the clerk. If you overload them, they might just put your request in the circular file (trash).
One more site to check is
Find a Grave . This is a wonderful site created by volunteers. I found photos of several graves of my ancestors on this site. You won't find everyone in your family, but you will probably find someone and that's better than no one.
If you know what cemetery your ancestor is buried in, you can contact the sexton or caretaker (providing there is one) and request the burial records from them. This is a good way to find other relatives who are buried nearby.
This post mainly focuses on death and burial records, because that's were I am in my reseach. The process is pretty much the same for finding marriage and birth records, but beware, birth and death records were not required until the very latter part of the 19th century or early part of the 20th century. In that case we may need to use church records, and that's a whole other ball of wax. Because marriage records are a legal document, they are more readily available and began much earlier. More on that later.