What are the differences between the various Liturgy of the Hours volumes?

I'm guessing there are other publishers, but I'm speaking specifically about the Catholic Book Publishing English version of the Liturgy of the Hours. I was on a retreat last weekend where we used the Shorter Christian Prayer books and I only got a little tripped up when I used my regular Christian Prayer book. After the retreat, my wife got really into it and she wants to pray with me morning and evening prayers, but I only have one set of the 4-volume set as well as one large type and one regular Christian Prayer book. So, just to simplify things and so we might know what to expect throughout the year when praying together or with the parish (using Shorter Christian Prayer), what are the differences between the "Christian Prayer", "Shorter Christian Prayer" and the 4-volume liturgy of the hours sets?