If you are interested in learning about Iranian history, I recommend you the BBC documentary 'Iran & The West: The Man Who Changed The World'. It is a three part series, featuring interviews with most of the relevant actors.
First part: the revolution and hostage crisis
- Ahmadinejad, the current President of Iran, was the only one out of four student leaders who opposed the occupation of the US embassy
- The occupation of the US embassy started without Khomeini being informed. When he learned the news, he was first against the occupation and ordered the Foreign Minister to get the students out of the US embassy. But then flipped and gave his blessing to the occupation. This move, which forced the entire Iranian government to resign, pushed the moderates out of the revolution. Khomeini became supreme leader.
- The hostage taking was initially undertaken to force the US to send the Shah, who was at the time in the US, back to Iran. But it continued after the Shah left the US. For the release of the hostages, the US returned assets to Iran that President Carter had frozen before.