Aragorn's father
 

The books tell us, that Aragorn is Isildurs heir and that he is Arathorn's son. But I have to confess I don't know anything about Aragorn's father, when he died or why he wasn't king of Gondor, cause as Aragorn's father he must have been a heir to Isildur, too. Who knows more?

Quite a lot of people, you'll find. [img]smilies/smile.gif[/img] Welcome to the forum, hope you enjoy it here... certainly you will find a source of ready Tolkien lore to fulfil your most fervent desires, if that is what you seek.

The answer to your question is found in the Appendices, but I'll explain it in brief here. After the death of Ondoher of Gondor and his sons, Arvedui -- the last king of the Numenorean North-Kingdom Arnor (the ruined kingdom; have a look at your LotR map), made a claim on the throne of Gondor; thus the two kingdoms of Arnor and Gondor would be united, and under the man who could claim the most clear link to the throne (Arvedui, being a king of the North-Kingdom, was descended from Isildur Elendil's son; the kings of Gondor traced their line from Anarion his second son).

The claim was rejected, and the throne givin to the victorious royally-linked Gondorian general, Earnil, instead. The next year Arnor was overrun by Angmar and vanquished. Arvedui perished afterwards trying to escape by sea, in a massive storm. A huge Gondorian force, under Earnur Earnil's son, then joined up with the Elves of Lindon (the Second Last Alliance [img]smilies/smile.gif[/img]?) to destroy the armies of Angmar, but they could not rebuild Arnor and the North was left desolate.

However Arvedui's son had survived, and thus the line of Elendil was preserved in the North unbroken -- by the Chieftans of the Rangers, the wandering Dunedain of the North who survived the ruin of Arnor. They were allied with Rivendell and secretly guarded Eriador.

When Earnur was killed in Gondor without an heir, the rule of the Stewards began. The existence of the northern Chieftans was unknown for long, and if it eventually was was ignored in the face of greater problems. Thus Arathorn was a Northern Chieftan and not a king.

Aragorn II, his son, was the one that rose up and took the crown of Gondor. Mordor defeated, the kingdoms of Arnor (rebuilt soon after), to whom Aragorn was the rightful heir through Arvedui, and Gondor of Elendil, were united under his High-Kingship.

The proposal of Arvedui thus happened eventually, but not for a long while.

i believe Arathorn was slain in battle around 2930 with the Orcs

Yes, Arathorn was slain in battle when an arrow pierced his eye.

Was Arathorn directly descended from Isildur? I can't remember if there was ever a Kinstrife in Eriador or childless rulers.

Well, again this can be found in appendix A to The Lord of the Rings, but yes. Aragorn was Isildur's direct descendant in the male line, the succession having remained unbroken among the Northern Dúnedain. No childless rulers are mentioned, although there was some strife between Arthedain, Rhudaur and Cardolan following the division of the kingdom, largely over the possession of Amon Sûl.

Most of the history of Gondor and Arnor can be found in Appendix A to The Lord of the Rings, sections ii, iii and iv. For future reference, basic questions like this ought to be posed in Novices and Newcomers.

since Aragorn was only 2 when Arathorn died, who then became cheiftain, or regent lord of the Dunedain?

also when did Aragorn and Gelrion(sp?) his mother leave for rivendell?

Gilraen.

Was Aragorn taken straight to Rivendell after his father died? When he was 2? I would answer directly but I am unsure whether I am right.

You are correct Meela, according to the appendices Aragorn and Gilraen went to Rivendell when Aragorn was 2, the same year his father Arathorn is slain.

.. There is no record of who commanded the Dúnedain Rangers in the absence of a Chieftain, which was the title given only to the eldest line of Isildur. I would presume that command would fall to the senior captain at the time.

Didn't Aragorn's Father die after Gilrain took Aragorn to Rivendell.

I'm assuming that after the family reached Rivendell, Arathorn went out upon errantry with Elladan and Elrohir, and that was when he got shot with the Orc arrow. Elrond (due to a certain amount of guilt to be sure) probably offered Gilraen (and Aragorn) a secure, safe place to stay, knowing that the forces of evil would come after Aragorn soon.