Answer: If Prince Albert II, who isn't married, never has any children, the next ruler would be his elder sister, Princess Caroline. If Caroline had predeceased Albert, or decided to give up her right to the throne, it would go to her oldest son, Andrea Casiraghi. Monaco's succession goes by primogeniture, with preference given to males. That means the ruler's sons would inherit first, in order of their birth. If there are no boys in the family, the throne goes to the oldest daughter.
After Andrea (assuming he has no children by this time), the next in line would be his younger brother, Pierre Casiraghi, then their sister, Charlotte Casiraghi, and their half-sister, Princess Alexandra of Hanover. After all Princess Caroline's children and their heirs are exhausted, the succession would got to Prince Albert's younger sister, Princess Stephanie, and then her children.
Diane in Buffalo, N.Y., asks: If the rules changed in 2002 who was to become the next ruler after Prince Rainier? The throne goes to Albert now, who would have gotten it if the rules did not change?
Answer: Albert, since birth, has been the heir to the principality, but until 2002 the situation was a little tricky. The constitution said only direct heirs of the ruling prince could inherit. That meant that if Albert, who is a bachelor, succeeded to the throne but never had children, Monaco would become a protectorate of France on his death. In 2002, Prince Rainier had the constitution amended to provide that if the ruling prince dies without direct heirs, power can pass to his siblings and then their children. Albert has two sisters, and they each have children, so there's now no danger of running out of heirs.
Lauren in Atlanta says: With the recent press of Prince Rainier's death, his family name of Garibaldi has been used often. Why is this not the case with the royal family?
Answer: The royal family of Monaco's name is Grimaldi, not Garibaldi. The Grimaldis have ruled in Monaco for 700 years. In Britain, the House of Windsor rules. Maybe it seems that you don't hear it very often because people who are directly in line for throne generally don't use a last name -- they don't need to. However, Prince Edward, the queen's youngest son, has a young daughter known as Lady Louise Windsor.
Charlotte in Houston asks: Why didn't Prince Rainier become King Rainier when he assumed the throne as a youth. In England, Princess Elizabeth became Queen Elizabeth II when she assumed the throne. I do not understand the titles being so different.
Answer: Monaco is a principality, not a kingdom, so its ruler is a prince, not a king. In Monaco, the ruling prince is styled His Serene Highness, or HSH -- which is a considered a step below HRH (His or Her Royal Highness). Monaco's lower ranking probably has a lot to do with its size and the fact that although it is an independent state, it has in the past been a protectorate of both France and Spain.
Willy in Miami asks: Is Prince Albert gay?
Answer: There's been a lot of speculation about that, but Albert says he is not gay. He has been linked romantically with a number of beautiful women, including supermodel Claudia Schiffer. But as long as he remains single, some people will probably continue to speculate.