Who or what is the Dalai Lama?

A lama is a Tibetan monk, but what is a "Dalai" lama? Who is the 14th pope/priest-king of the Yellow Hat school of Vajrayana Buddhism? We'll get to know his story, his function, the issue he has with China -- which invaded and still occupies Tibet behind Mt. Everest -- and his strange alliance with Washington, DC. There's a reason we as Americans hear so much about him. He is beloved, and his books are very popular, but he has his detractors even inside of Buddhism. What form of meditation or practice does he suggest?