Dr. Doom's mother, Cynthia, was a sorceress who sold her soul to the devil (Mephisto) for more power. When she passes away, Dr. Doom makes annual trips to hell in an attempt to rescue her. In Dr. Doom and Dr. Strange: Triumph and Torment, he finally succeeds in securing his mother's freedom... at any cost.
After stealing power from Zebediah Killgrave (Purple Man), Dr. Doom uses his new mind control powers to eliminate free will and take over the world. Doom, having succeeded in his push for world domination, soon grows bored. During a fight with the Avengers, Doom basically lets Purple Man escape just to shake things up a little bit.
The Secret Wars story arc began back in the 80's and became relevant again in the last year or two. In the story, Dr. Doom (and some other, lesser, characters) are faced with a strong enemy called The Beyonders. The Beyonders are a race of omnipotent aliens who are hellbent on destroying the multiverse. In order to stop the Beyonders, Dr. Doom destroys the multiverse himself.
Molecule Man sacrifices himself so that Doom can absorb his power. Doom then travels throughout various alternate realities to murder all other versions of Molecule Man and absorb their power as well. When he is strong enough, Doom finally takes on The Beyonders alone.
In Fantastic Four Annual #2, Jack Kirby and Stan Lee give us our first real look into Dr. Doom's origin. From the issue: "As a young boy, Victor von Doom's father --a gypsy healer-- is asked by the King's men to heal the King's wife. Werner von Doom tries his best but fails, and when the King's wife later dies of her illness he sends his troops to get Werner. Werner and his son Victor then fled into the mountains where the father wrapped the boy in his own coat while they hid in the snow and ice. They were later found by the rest of their clan and taken back to the village. There Werner died of exposure, but not before asking Boris to look after his son. Boris took this to mean to watch out for the boy, not look after him. Furious at the death of both his father and mother at the hands of the King, Victor dug up his mothers old chest filled with mystical potions and books."
Fantastic Four: Books of Doom is a retelling of Dr. Doom's origin story that gives us more insight into the character's development. The first few issues of this arc revolve around Doom's relationship with his mother and that's important because it gives more credence to his annual visit to hell. The book goes on to explain Doom's facial scarring, his suit, and various other important aspects of his character. As far as I'm concerned, Books of Doom is a must read for anyone trying to learn about Dr. Doom's background.
This should really be listed as Fantastic Four #57-60 but I chose to highlight #58 for one very specific reason- Doom is winning!
In Fantastic Four #57 Dr. Doom tricks the Silver Surfer into standing before a machine that steals his power, transferring it to Doom. In Fantastic Four # 58 Doom uses Silver Surfer's board to fly to New York and attack the Fantastic Four. One by one all of the members of the Fantastic Four fall to Doom's new power- but he does not kill them. Instead, Doom tells them that resistance against is plans is futile and gloats about his victory.
The story of Fantastic Four: Unthinkable revolves around Dr. Doom and his desire to return to magic- feeling that science and technology are no longer a suitable means to conquer his enemies. In his pursuit of power, Doom makes a deal with the Haazareth Demons that will increase his power. This is the infamous book that sees Dr. Doom reunited with Valeria, the love of his life, only to betray her and make a new suit of armor from her skin.
Fantastic Four Vol. 1 #5 makes this list for the sole reason that it is Dr. Doom's first appearance.
Fantastic Four #258 is an issue that offers a unique look into the daily life of Dr. Doom. This issue sees a doombot destroyed for failing a mission, a potential rival slain, and offers a unique glimpse into the relationship Doom shares with his son Kristoff.