A note to the original poster:
If you want the DT&I book, try The Model Railroad Shop in Piscataway, NJ at 732-968-5696. The store is one of Morning Sun's principal dealers and often still has titles which have sold at the publisher. I have met with success on a number of occasions in this manner. Even if Morning Sun has sold out, The Model Railroad still doesn't attempt to charge a premium like some others might. They mail order regularly so shipping the book to you won't be a problem for them.
Good luck,
Bob