This book was originally intended to be renumbered #1 with this issue. House ad for it as #1 first issue were advertised in DC comics in late December and early January. The house ads were changed in mid January to delete any reference to a #1. (Info from Bob Bailey.)
On-sale date from ad in Sea Devils #16 and copyright registration.
letters submitted by: Ted Renault, R. M., Thomas Graham, Robert Dale Henshaw, Paul Gambaccini, Michael Colby, Jerry Phillips, Steve Tamerius, George Jackson, Robert Sladek