"I have much to say in this book about the final canonical shape of the OT, arguing throughout that its purpose was to provide the books of the OT with the best possible context for viewing them messianically. Sometimes the messianic influence on the final shape is conspicuous. In other cases, it may be merely a matter of what books are placed together and what order they follow (contextuality). The book of Ruth does not stand between the historical books of Judges and Samuel in the Hebrew canon. There, Ruth, whom Boaz called "a virtuous woman," is placed after the poem in Proverbs 31 that begins with the question 'Who can find a virtuous woman?'"
-from "the meaning of the pentateuch", as quoted at my husband's blog