This book is a memoir; the characters are real people. The author and narrator is Barack “Barry” Obama, who at the time of this writing was a Harvard graduate who was working as a rights organizer within the black community of Chicago. He had not yet become a state senator. He had been born in Hawaii.
The rest of the people who appear most often in the narrative are members of his extended family. These include his mother, Ann Dunham Obama Soetoro, an anthropologist, who moved from Hawaii to Indonesia. Maya is Barack’s younger half-sister, who came along after his mother married an Indonesian man named Lolo. Barack’s father is Barack Obama Sr., a Kenyan of the Luo tribe, known as “The Old Man,” who met Ann when he attended college in Hawaii. They were married for about three years. Young Barack was raised mostly by his maternal grandparents, Madelyn “Toot” Dunham and Stanley “Gramps” Dunham, who were both originally from Kansas but who relocated to Hawaii after World War II. Barack has a number of half-siblings based in Kenya, including half-sister Auma and half-brothers Roy, David, Mark, and Bernard. He also met there some of his aunts, his father’s sisters: Zeituni, Jane, and Sarah.
See the Wikipedia article on Dreams from My Father