The two UT's?!? What is the book that I have then?

[Aiwendil]

There's no reason why you have to read them in order.

It's not necessary to read them in order, certainly, but the sequential approach does have its virtues. References to material from earlier volumes abound and will go over the head of one who hasn't read them. Overall, I think that reading them in order provides the most coherent, intelligible experience.