Havana, Cuba (CNN) -- Former Cuban President Fidel Castro once again dominated his country's airwaves Monday during the televised presentation of an event for his new memoir, "Fidel Castro: Guerrilla of Time."
The existence of the two-tome, 1,000-page memoir was not publicly known until Saturday, when the official state-run newspaper Granma ran excerpts of the book and comments from Castro made during a reported six-hour book party.
What was advertised as "the first part" of the book party aired for about 1½ hours on Cuban television on Monday. It was one of the retired leader's most extensive public appearances since a 2006 illness forced him to step down after nearly 50 years in office.
His brother Raul Castro took over from Castro as president and recently announced that officials would be restricted to term limits of 10 years.
Once a ubiquitous presence in Cuba, since his retirement Fidel Castro often has disappeared from public view for extended periods, leading to frequent rumors about his ill health.
Wearing a black Adidas track suit, Castro spoke in a hoarse but even voice. Although noticeably frail, Castro, 85, appeared Monday in good spirits.
"I have nothing better to do than this," joked Castro to the select audience at the book launch. "You want to be useful. This seems like it has value," he told the crowd.
Government officials next to Castro on stage read from the first book of the memoirs, which centers on his life leading up to the 1958 revolution that swept him into power.
The book is based on interviews between Castro and Cuban journalist Katiuska Blanco.
In between readings, Castro told the audience he stays busy poring over the latest world news.
"Internet is a revolutionary instrument that allows receiving and transmitting ideas," he told the audience, "It's something we should use."
Castro cited current flash points like Iran and the disputed Falkland Islands as subjects he was currently immersed in. He also mentioned the Republican primaries taking place in the United States and said he considered the voter turnout to be low. "People aren't interested," he said.
Speaking about Syria, Castro said, "What happened in Libya won't happen there," referring to the overthrow and killing of Libyan dictator Moammar Gadhafi last year.
In Cuba, Castro then said, "We have a duty to fight until the last minute."