This issue has variants.
On-sale date from DC Releases #13.
Pencils and inks credits from DC Releases #13. Color credits confirmed by Anthony Tollin.
Story continues in Detective Comics #551. Non-advertised, Crisis on Infinite Earths mini-series,two-panel-sequence-cameo with The Monitor (Only hands shown with voice), and Lyla [Harbinger]
Letters of comment from David Alan Wright, Jeffrey Lowndes, Ken Morefield, Rick Steel, Craig Paeth, Charles D. Brown, Delmo Waters, Cory R. Strode, Alan Hillis, Jeff Grant and Lloyd Ferrell.