Historians thought Nixon was the last president to record his phone calls. Reagan proved them wrong. It was 3 a.m. on an October morning in 1983, and President Ronald Reagan had just been roused from sleep by his secretary of state, George Shultz. Still in his pajamas, the president met with Shultz in the living room of Reagan's Georgia hotel suite, where the president was supposed to be on a golfing vacation. They had an urgent matter to discuss: The Organization of East Caribbean States was pleading for American support in Grenada, and the president had to decide whether, in a matter of hours, he wanted to send an American-led invasion into the tiny Caribbean island. Complicating matters was a "loose source," as Reagan later described it, one that threatened to jeopardize any military plans the president set in motion. The tense details could've been plucked from the pages of a Robert Ludlum novel, but they were recounted by Reagan himself in a profusely apologetic phone call to British Prime Minister Margaret Thatcher later that day. "I guess it's the first thing we have done since I've been president in which the secret was actually kept until it happened," Reagan told Thatcher in an attempt to explain why the prime minister wasn't consulted before American forces were launched. The scene is from one of a handful of historic conversations recorded by Reagan and discovered by author William Doyle almost two decades after the Freedom of Information Act request he made in 1996, according to the New York Post. RELATED: When Reagan apologized to Thatcher for a U.S. invasion Steve Branch, an archivist at the Reagan Presidential Library in California, told the New York Post "that the tapes are the first audio recordings of White House Situation Room telephone conversations the library has released to date." For a full transcript of the call, click here. Although Reagan was one of the most publicized and scrutinized of U.S. presidents, the tapes open a new window into his presidency. "Until now, taping was thought to have stopped in the Nixon era," Doyle told Fox News. I discovered that was not the case. Doyle also told Fox that Reagan recorded many of his phone calls with heads of state through the Situation Room switchboard, to maintain an accurate record of conversations that often included translators and bad connections. The author told the New York Post that he selected five recordings for release because of their historic value. Among them: Two phone calls with then-Pakistani President Muhammed Zia ul-Haq, with whom Reagan is heard discussing western hostages and terrorism -- including how to respond to the hijacking of TWA Flight 847. Another recording airs a heated 1983 exchange with then-Israeli Prime Minister Menachem Begin about Israeli troops in Lebanon. There is also a chat with Syrian President Hafez al-Assad, father of current Syrian President Bashar-al Assad, which comes after the elder Syrian leader is forced to wait for more than 13 minutes while translators struggle to explain what's taking so long ... as Reagan finishes up a horseback ride at his California ranch. Failing to get an accurate translation, Assad is told the American leader apologizes and was on a "farm." Finally, according to the New York Post, Reagan says: "Mr. President, let me take this opportunity to extend my congratulations on your reelection to a new term as president of Syria."