A special item -- not in Marquand's usual vein of adroit social comedy nor up to the standard he has set himself. However, on his name the book will sell, slight as it is. The subject matter is one that is everywhere evident today -- what is happening -- what will happen -- to the haphazard war marriages, based on rootlessness and emotional upheaval and homesickness. This story is told by a newspaper correspondent to whom has been given the unwelcome task of looking up a young flier's parents in East Orange and the wife he brought home to them and the baby he had never seen. What Briggs finds -- and rather cynically the way in which it ties in with the none too glamourous backgrounds of the majority of our heroes --makes the center of the story. Briggs has to take back to Boysie the news that it's another case of marriage in haste -- with the ending this time ""repent in haste"" rather than leisure. Just another off-again, on again affair. The publishers have given the book a jacket that strikes a cheap note, perhaps unintended.