THE GATE OF TIME 1966 Belmont 1st Printing	THE GATE OF TIME 1970 Belmont Reprint	THE GATE OF TIME 1974 Quartet 1st British Printing	expanded and retitled TWO HAWKS FROM EARTH 1979 Ace Reprint
expanded and retitled TWO HAWKS FROM EARTH 1985 Berkley Reprint	expanded and retitled TWO HAWKS FROM EARTH 2009 Monkey Brain Reprint