- Script
- Chip Zdarsky (credited)
- Pencils
- Leonardo Romero (credited)
- Inks
- Leonardo Romero (credited)
- Colors
- Jordie Bellaire (credited)
- Letters
- Clayton Cowles (credited)
- Editing
- Dave Wielgosz (credited) (editor)
- Genre
- superhero
- Characters
- Batman [Bruce Wayne]; Robin [Dick Grayson]; Batman of Zur-En-Arrh; Professor Achilles Milo; Alfred Pennyworth; Thomas Wayne; Martha Wayne; Commissioner James Gordon; The Joker
- Synopsis
- In a story set in the past, Batman is recovering from an attack on his mind by Professor Milo, and to resist future similar attacks, he conditions his mind, inspired by a past meeting with the Batman of Zur-En-Arrh. His new conditioning is put to the test when he investigates a new string of killings by the Joker.
- Reprints
Batman originally encountered Professor Milo in Detective Comics (DC, 1937 series) #247 and Batman (DC, 1940 series) #112. Batman originally encountered the Batman of Zur-En-Arrh in Batman (DC, 1940 series) #113.