Letters credit from Todd Klein via http://kleinletters.com/.
The Idiot Root story continues in Detective Comics (DC, 1937 series) #639.
Letters of comment from Jason Crase, John Richardson, jay McIntyre, Matt Springer, Melissa Page, Marc Johnson, Matt Funk, "Name withheld", Zack Keener and Dr. Andrew C. Kolbert. Includes "From the Den" column.