TOMORROW, Warner Books, one of the biggest commercial publishers
in the United States, marks the official publication date of
''Batman: Year One,'' a 96-page color comic book about a
neurotic superhero who is a successor to the original caped
crusader. This event follows the success of the 1986 Batman
book, ''The Dark Knight Returns,'' which has sold 85,000 copies.
And this fall, Warner has high hopes for ''Brought to Light,'' a
72-page comic it is issuing about the Iran-contra affair, no
less.  An academic publisher, the University of California
Press, has also discovered that comics are not just for kids. It
is already on its third printing of a 313-page comic book,
''Japan Inc.,'' about the Japanese economy. The story is told
through the adventures of a fictitious trading company coping
with floating exchange rates and protectionist American
autoworkers who take sledgehammers to a Japanese car. The comic
book, which appeared in late June, has 32,500 copies in print in
the United States and 600,000 in Japan