I have this old book that I would like to know when it was printed, but I cannot read the dates. It has three dates that are MCMXXV----MCMXXVIII---MCMLV. Could one of your experts please tell me what those letters mean and what order is the one you go by to date it.

They are called Roman Numerals and Here's a link (http://en.wikipedia.org/wiki/Roman_numerals) that will give you a full breakdown.