I'm a little confused by the amount of different Turks that pop up throughout history, I've heard about central-asian Turks in reference to raiding steppe tribes that harassed everyone from ancient Sumer right the way up to Persia, the Turks who encountered the Mongolians and of course the modern day state of Turkey.
I was wondering if those Turkic people were related to, or responsible for the modern state of Turkey, or is this a situation similar to the European definitions of Barbarians, Vandals and Goths? (as in a somewhat loose definition of those who threaten "civilised society").
Who are the Turks?
Short answer: yes, Anatolian Turks are related to some of the Central Asian Turkish groups we see throughout history.
Long answer: the Anatolian Turks are Oghuz-speaking Turks who first arrived in Anatolia during the eleventh century. These (soon to be) Anatolians had migrated to eastern Iran from Central Asia during the early eleventh century and worked as mercenaries for the Ghaznavid dynasty. The Ghaznavids were founded by a Turkish mamluk (military slave) who had served the Iranian Samanid dynasty who ruled over Central Asia and eastern Iran. The descendants of an Oghuz Turk called Seljuk assumed command of the Oghuz Turks in Central Asia and eastern Iran, and led them to victory against the Ghaznavid dynasty at the battle of Dandanqan (1040). The Seljuks and their armies proceeded to gradually conquer Iran and Iraq, their leader Toghril Beg entering Baghdad in 1055. In order to control the unruly Oghuz tribes, the Seljuk dynasty sent the tribes to raid the Christian states to the west (including Byzantine Anatolia). Alp Arslan, the successor and nephew of Toghril Beg, assembled a large army and marched west to invade the Shia Fatimid Caliphate of Egypt and Syria. However, this army shocked the Byzantine emperor Romanos Diogenes into assembling his own army and fighting the Turks at Manzikert (1071). Romanos lost, and was captured; the Anatolian nobility fled to Constantinople to intrigue in selecting a new emperor while the Oghuz Turkish tribes did their usual pastime of raiding the region. The difference now being that imperial authority was absent, resulting in the Oghuz Turks staying in Anatolia. The Ottomans were one of these Oghuz tribes, though it's probable that they migrated to Iran because of the Mongol invasions of the thirteenth century.