There are several books on the raid of course, but if you are only going to read only one, then this one seems to best cover why the actual mission never took place, why it ended during the delivery process.
The Guts to Try: The Untold Story of the Iran Hostage Rescue Mission by the On-scene Desert Commander
http://www.amazon.com/The-Guts-Try-On-scene-Commander/dp/0517577143
“A powerful eyewitness account of the disastrous April 1980 attempt to rescue the American hostages in Tehran. Kyle, an expert in Special Operations and the officer in charge of the Air Force component, describes the mission from the earliest planning at the Pentagon through the subsequent rehearsals to the operation in Iran. Criticizing analyses by other participants, he offers his own diagnosis of five factors that contributed to the mission’s failure: the weather forecast, poor communications equipment, pilot decision error, restrictions on tactics, and a poor flight plan.”
Those restrictions came right from Carter. Thanks for the link.