Analysing events inside North Korea is notoriously difficult, and the question of succession is mired in doubt and speculation. The BBC News website looks at some of the figures closest to leader Kim Jong-il.
Tales from dissidents and past aides have created an image of Kim Jong-il as an irrational power-hungry leader who allows his people to starve while he enjoys dancing girls and cognac.
But the sister of Sung Hae-rim - one of Kim Jong-il's former partners - has painted a different picture. She describes him fondly in her memoir, The Wisteria House, as a devoted father and sensitive, charismatic individual, although she admits even those closest to him were fearful of him.
Kim Ok is believed to have been the North Korean leader's long-term private secretary until news reports in July 2006 said she had become his new wife.
An official, quoted by South Korean media, described her as "virtually North Korea's first lady".
A former musician, Kim Ok is reported to have become Kim Jong-il's secretary in the early 1980s and began living with him at some point after the death of Ko Young-hee.
The 42-year-old has accompanied Mr Kim on several of his inspection tours to military and industrial facilities, and travelled with him to China in January 2006.
"I heard she is very wise and clever," the official told Yonhap news agency.
Kim Jong-il's brother in law was, until early 2003, was thought to have been one of his closest confidants. He was vice-director of an extremely powerful government department - the Organisation and Guidance Department - and high-profile defector Hwang Jong-yop described him as "the number-two man in North Korea".
But he and his circle of friends were reportedly "purged" and Chang Song-taek sent away for re-education in early 2004 after they attended a luxurious wedding party.
Analysts have suggested that the real reason for his removal was either that Mr Chang and his brothers were perceived as rivals to Kim Jong-il's leadership or that he and his circle constituted the greatest threat to the faction backing one of the 'Dear Leader's' sons by Ko Yong-hui for succession.
However, South Korean media reported in January 2006 that Mr Chang was back in the North Korean hierarchy - appointed to the less powerful position of first deputy chief of a committee department in charge of public labour work.
He is married to Kim Kyung-hee, Kim Jong-il's younger sister (born 30 May, 1946).
According to the South Korean newspaper Munhwa Ilbo, Kim Kyung-hee has been living separately from her husband for some time. The couple have a daughter.
Ko Young-hee, described as Kim Jong-il's favourite consort, died of cancer in 2004 after receiving treatment in Europe.
Little is known about her, except that she was born in Japan to ethnic Koreans and is said to have caught Kim Jong-il's eye while working in a state dance troupe.
She is the mother of two possible successors, Kim Jong-chul and Kim Jong-woong.
A North Korean army document released in 2003 and seen in the South showed an "idolising campaign" had begun to raise Ko's status.
The report referred to an "esteemed mother" who was the "most loyal" companion to Kim Jong-il, leading to speculation that her son Kim Jong-chul was being groomed for the leadership.
Kim Jong-nam, 35, is Kim Jong-il's eldest son.
Sung Hae-rang, the sister of Kim Jong-nam's deceased mother Sung Hae-rim, has written in her memoir The Wisteria House that Kim Jong-il was extremely fond of Kim Jong-nam and was pained to be parted from him when he was away.
Like his half-brothers, Kim Jong-nam studied in an international school in Switzerland.
His chances of succession appeared to be ruined when, in 2001, Japanese officials caught him trying to sneak into Japan using a false passport. He told officials that he was planning to visit Tokyo Disneyland.
Some analysts argued that he may have been forgiven by his father, as there is precedent for the regime re-instating disgraced figures after a period of atonement. Confucian tradition also favours the oldest son.
However, in January 2006 he was found to be living in Macau, which suggests he remains out of favour by his father.
Kim Jong-chul, 25, studied at an international school in Switzerland. He works in the WKP propaganda department.
Some analysts believe he is being groomed as Kim Jong-il's successor. His mother, Ko Young-hee, is said to have been the North Korean leader's favourite consort.
However, Kenji Fujimoto, the pseudonym of a Japanese sushi chef who spent 13 years cooking for Kim Jong-il, has written that the leader considered his second son "no good because he is like a little girl."
Kim Jong-woong, aged around 22, is the second son of Kim Jong-il and Ko Young-hee. Like his older brother, he is thought to have been educated abroad.
A Japanese sushi chef who worked for Kim Jong-il for 13 years up to 2001 believes Kim Jong-woong is the heir apparent. He said that he "resembled his father in every way, including his physical frame".
But analysts have argued that he is still too young to be nominated successor.