These four short mysteries by Wallace Maison are packed so tight with murders and theft that only the inconspicuous traveler Mr. Green can perceive the motives and point to the culprits. -The Man Dressed In Black -The Unwanted Passenger -The Yellow Diamond Ring -The Martyr's Strange Course & Epilogue Whether you sympathize with the victim or the murderer in this collection of short mysteries, each crime had to be solved before the next stop on the northbound California train.