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

[Thinlómien]

I'm probably going to buy the HoMe series. I have already a book in Finnish, which is called Keskeneräisten tarujen kirja and it's original/english name is Unfinished tales of Númenor and Middle-Earth. So I was very confused as I found out that there are actually two UT's.
I don't want to pay for a book that I already have, since I don't have much money, so could someone help me to identify my book: is it completely different than this two UT's? Or is it only the first part? Or does it include both? This book is first published in 1980 by George Allen & Unwin Ltd. It contains following chapters (I've translated the names bay myself so they aren't maybe correct):
- First Part: First Age
I Of Tuor and his coming to Gondolin
II Narn i Hîn Húrin
- Second Part: Second Age
I The Island of Númenor
II Aldarion and Erendis
III The Heirs of Elros
IV The Story of Galadriel and Celeborn
- Third Part: Third Age
I The Tragedy of the Gladden Fields
II Cirion and Eorl
III The Journey to Erebor
IV The Search for The Ring
V The Battles in the Fords of Isen
- Fourth Part
I Drúedain
II Istari
III Palantíri
I'm very grateful, if someone helps me...