Use commas to set off a word or a group of words that is not essential to the meaning of a preceding noun or pronoun, such a word or group of words is a nonrestrictive appositive. The appositive usually restates or gives more information about the noun that precedes it in some way.
Dr. Pulaski, the principal speaker, is an industrial psychologist.
Her first book, Principles of Effective Management, was published in 1984.
He, Charles Houston, bought and renovated the building a few years ago.