It's interesting, Estelyn, that you should see 'Tale' as a misleading title, since Tolkien would not have thought it so. Here he uses the word in an extremely archaic sense, with the rough meaning 'list, reckoning or tally'. In fact, Tolkien had been composing such annals for decades before he began
The Lord of the Rings, in an attempt to establish the chronologies of Beleriand and Valinor. The Old Norse word
tál has this very meaning and a similar pronunciation. It forms part of the compound
Dvergatál, the section of
Voluspá from which Tolkien lifted many of his dwarf names.
Tolkien's earliest annals bear a striking resemblance to those written by medieval scribes, particularly that great monument of Old English historiography, the Anglo-Saxon Chronicle. In fact the
Godéðles géargetæl, with its years in Roman numerals, two-column format and preponderance of
Hér (literally 'here', but meaning 'in this year') as an opening word for its entries, is almost identical to the Old English document. The word
géargetæl itself means 'annal' or, more literally, 'year-tale, tale of years'.
It's interesting that Tolkien saw fit to offer a chronology for his stories, since the annal is a vital tool in establishing the dating of events in medieval narrative. In particular, Scandinavian historical sagas are very concerned with details of personality, appearance and conversation, but date events, when they date them at all, by reference to other significant happenings, reigns of kings and ecclesiastical appointments. Often some quite complex cross-referencing with contemporary annals is required before a satisfactory date may be found, and doubtless Tolkien had to do this at some point in his career. Once his own narrative was finished, he decided to give his underlying history its vital shape by supplying just such a structure, which he named, as one would expect, in a literal rendering of Old English. In this respect the Tale of Years is another example of Tolkien's fiction feeding on his professional interests, producing greater verisimilitude.
As regards the actual contents of the Tale of Years, I shall have to post again when I have my books to hand, but as a potted history of the Second and Third Ages, I've found it to be invaluable. It's just like Tolkien to re-tell the story he's just told in a completely different format, giving its events an entirely different flavour.