Do I use a comma in series of names before the word and?

Yes, you should use a comma in a series of names before the word "and". This is called the Oxford comma, and while it is not strictly required in all styles, it is generally considered good practice and helps to avoid ambiguity.

Here are some examples:

With the Oxford comma:

* I went to the store with John, Mary, and Bob.

* The winners were Emily, Sarah, and David.

Without the Oxford comma:

* I went to the store with John, Mary and Bob.

* The winners were Emily, Sarah and David.

In the examples without the Oxford comma, it could be interpreted that Mary and Bob are a single entity (like a couple), which isn't necessarily what you intended. The Oxford comma makes it clear that each name is an individual.

Here are some additional points to consider:

* Style guides: Some style guides, like the Chicago Manual of Style, recommend using the Oxford comma, while others, like the Associated Press Stylebook, do not. It's always best to check the specific style guide you're using.

* Clarity: Even if the style guide you're using doesn't require the Oxford comma, it can be helpful to use it if it improves clarity.

* Personal preference: Ultimately, the decision of whether or not to use the Oxford comma is up to you. Just be consistent in your writing.

Remember, the most important thing is to be clear and concise in your writing. If you are unsure about using the Oxford comma, err on the side of clarity.