The second edition, which adds Joanna Dewey to the authorial team, makes a good book even better.
Substantial revisions improve and update the text.
Insights from recent scholarship are incorporated while maintaining the focus on Mark as a story. An Afterword on the ethics of reading has been added. Of special note for classroom use is their English translation of Mark. It allows those who do not read Greek to gain a sense of the style of the original. Two new appendices with exercises for students are also valuable.