Too Late Now

One of the great frustrations with trying to re-construct your family history is the lack of information about various individuals that arises out the assumption that there is no need to write things down because someone will remember. Well, what happens when no one remembers, or when there is no one around to remember?
This is a picture of my father Bill Campbell taken around 1930. Beside him is his sister Jess, and in front of them are Jack and Mary, their two younger half-siblings (same mother, different father).

I do not know when Jess was born and I have no idea whether she is still alive. I know that both Jack and Mary have died, but I do not know exactly when, and I can only guess at when they were born, based on the age they appear to be in this photograph.
Beyond staying in touch with his mother, my father had very little to do with his family and so my exposure to his siblings was minimal. Jack married, but had no children. Mary remained a spinster. Jess married and had one son, but I only remember seeing him on a few occasions when I was still in public school. Of course, it never occurred to me when I was in my teens to ask the sort of questions that would prove helpful in later genealogical research. Too late now.