Iran possesses the second-largest reserves of oil in the world, as well as the second largest natural gas reserves. Thus, their importance is hard to overestimate.
U.S. recent involvement in Iran began with our participation in the overthrow of its democratically-elected leader on 8/19/53 because of his decision to nationalize the oil industry - with payment and the intent to retain most/all workers. Subsequently, we further aggravated our relationship by pushing for exempting U.S. citizens from Iranian laws, and our support for land reform as a defense against Communism.
In 1974 the U.S. signed a ten-year agreement to supply Iran with enriched uranium, while Iran planned to order 5 nuclear power plants from France. Meanwhile, the U.S. supported Shah eventually turned the populace against him by stifling dissent, and when the U.S. allowed the deposed Shah into the U.S. for medical treatment (Britain had prohibited), the U.S. began to be viewed as the Great Satan and the Iranian hostage situation followed.
Our alliance with and support of Iraq during the Iran-Iraq War became another problem, while U.S. political support for Iran was undermined by the Iran-Contra affair (weapons and parts to Iran for hostages being released in Lebanon and cash - the cash was then funneled to Nicaraguan Contras). The Vincennes affair (guided missile destroyer that negligently shot down an Iranian airliner), followed by our initial efforts to cover-up the error and Reagan's awarding the Captain a medal further soured our relationship.
Other problems included the Navy ship Stark - hit by an Iraqi missile, the U.S. initially blamed Iran and President Reagan made some very derogatory and inappropriate remarks aimed at Iranians), opposing a pipeline through Iran (made economic sense), refusing to allow Conoco to contract with Iraq because of Israeli lobbying, and the perception that U.S. foreign policy was made in Israel. (Bush I had complained in 1991 about the 1,000 Jews simultaneously lobbying Congress to allow American aid money to be spent enlarging settlements; his remarks punctured their effort, but he heavily lost Jewish counties in the next election. Currently many Christian fundamentalist goups also lobby for Israel.)
Relations improved late in the Clinton Administration when Secretary Albright expressed regret regarding our involvement in the 1953 regime change and supporting Iraq in the Iran-Iraq war. Unfortunately, according to Ansari, the Iranians decided to wait for a Republican president to move forward.
Bush II immediately shifted into reverse by reworking old allegations about Iran's involvement in the '96 Khobar (Saudi Arabia) towers bombing in '96. (Clinton dropped the matter in light of positive developments, his belief that the evidence was weak, and Saudi Arabia's failure to cooperate.)
Nonetheless, after 9/11, Iran's President and others were among the first to offer condolences, and many citizens demonstrated against terrorists. Despite the U.S.'s rude approach, it was agreed to support rescue missions from Iranian soil, and Iran did arrest fleeing Taliban and al Qaeda (though they did refuse to turn them over to the U.S.)
This cooperation was followed by Bush's "Axis of Evil" speech, and Israel's interception of a ship carrying arms from Iran to the Palestinian Authority. The result was that Iranian "hard-liners'" hand was strengthened. The Religious Council banned many Reformists (even incumbents) from running, and hard-liner Ahmedinejad was elected (made economic sense to the general public on the basis of his reform promises).
"Confronting Iran" closes with a summary of the nuclear standoff with the U.S. vs. Iran. Unfortunately the details are not clear; however, what is clear is that Iran was not without fault in this area. Regardless, Ansari makes a good point by stating that the U.S. has very few Iran experts, and rotating them out every three years is not a good idea.
Bottom Line: "Confronting Iran" provides a good understanding of the history of U.S.-Iran relations. However, it is sometimes hard to follow, due to sparse details and/or out-of-order material.