Batman: The Dark Knight Returns #1 is said by many to have ushered in the age of modern comic books.  Whether you agree or not, it is still a GREAT read and a huge Copper Age key.  It's Frank Miller at the pinnacle of his career.  First appearance of Carrie Kelly, who later becomes Robin.  This book is graded 9.6 NM+ with white pages by CGC.  This is the FIRST PRINTING.  No Batman collection is complete without this series.