There isn't too much online information on Ms. Cummings but I learned from a former client that, "she is kind, professional, and supportive, she loves lyric and she loves sweet!" Also, Mary works book by book.
There is a 2009 article, Made in Minnesota: The Rise of Agent Mary Cummings at Children's Literature Network.
You can see a few comments on submissions writers have made on Mary Cummings' listing at Querytracker.
Writer Maria Ashworth lists that she is represented by Mary Cummings on her website.
Mary Cummings can be queried via email with the entire picture book manuscript pasted into the body of the email. Read her entire submission guidelines on the Betsy Amster Literary website.
This post is part of the Monster List of Picture Book Agents. If you have any changes that you think should be made to this listing, please contact me or leave them in the comments. Thanks!