Why are both a comma and and used to separate the names of coauthors in a works-cited-list entry?

Note: This post relates to content in the eighth edition of the MLA Handbook. For up-to-date guidance, see the ninth edition of the MLA Handbook.

The MLA Handbook notes that “[w]hen a source has two authors,” you should “[r]everse the first of the names” and “follow it with a comma and and” before providing “the second name in normal order” (21):

Dorris, Michael, and Louise Erdrich. The Crown of Columbus. HarperCollins Publishers, 1999.

A comma is needed in addition to and so that the reader can easily distinguish the two names. In the example above, omitting the comma after “Michael” might cause the reader to momentarily misread the first name listed as “Michael and Louise Erdrich Dorris.”

Work Cited

MLA Handbook, 8th ed., Modern Language Association of America, 2016.