The Oxford comma
Also called the Harvard comma or the serial comma, using it has been mandated by the Oxford University Press for over a century. Not without good reason. That second comma can make a critical difference.
Here’s an example I made up:
I owe all I’ve become to my wife, my drill instructor and the president of my fan club.
Of course it ought to be:
I owe all I’ve become to my wife, my drill instructor, and the president of my fan club.
The classic example for pro-serial-comma folk is:
This book is dedicated to my parents, Ayn Rand and God.
Which of course ought to be . . . my parents, Ayn Rand, and God.
Another one I made up without any commas: I have experience with cooking dogs and lawyers.
(At times in my life I’ve thought about doing just that to certain members of both species.)
Proponents of the venerable serial comma are adamant about always using it. But there’s a small army of anti-serial-comma folk out there who argue with equal heat that over-using that second tiny paisley-like punctuator can also cause confusion and slow down the reader.
Book and magazine publishers generally prefer using it. Newspaper people generally don’t.
Nobody argues about some traditional uses, such as enclosing parenthetic expressions in commas. But there are many other instances of comma use that can be doubtful.
Over the years I’ve evolved my own solution to comma conundrums.
If a comma will help crystalize clarity I use one.
If it doesn’t I don’t.