13.3.8.1 Prefer the serial comma, as in A, B, and C
Conservatives, like Strunk and White, authors of the famous Elements of Style, recommend always using a comma before the "and" of a series of three or more members. In fact, almost all writers of style books favor the comma, if not all the time, at least whenever the series is in any way complicated.
Teachers, for their own dark reasons, like to teach against the current of their style books and leave students with the impression that the comma before the "and" is to be avoided.
Careful editors use the comma wherever the series has any complication.
Here is a complicated series showing the occasional need for the comma:
For dinner, we had ham, field greens, mashed potatoes and gravy and biscuits.
Assuming that the writer is not a fool, the solution is not to remove one of the 'ands'; instead, the writer meant that something was served together. But was it "potatoes and gravy" or "gravy and biscuits"? In short, was the meal served below or above the Mason-Dixon line?
The Southern dinner: For dinner, we had ham, field greens, mashed potatoes, and gravy and biscuits.
The Northern dinner: For dinner, we had ham, field greens, mashed potatoes and gravy, and biscuits.
If the sentence above requires a comma before the terminal "and" and if you feel an awful need for consistency, you will always use the comma before the "and" in series of three or more elements.
==>Guidelines ==>Conventions
==>Problems ==>Commas