Wikipedia contains spoilers.
The hero of the story is Peter Parker, who is a precocious teenager, but also a complete social outcast who is too shy to even approach Mary Jane, a girl from next door he is smitten with. His only friend is Harry Osborn, and even that is tainted with jealousy by the fact that Harry's successful father, Norman, favors the brilliant Peter over himself. Parker lives in Queens, New York City, New York.
On a student tour of a genetics laboratory, Peter is bitten by an escaped experimental spider that has been created with various traits from a variety of spiders. The spider's venom causes him to fall ill and he barely arrives home before collapsing into bed. After a difficult night's sleep while the venom alters his genetic makeup, he wakes up seemingly unharmed. However, he learns to his surprise that his body has changed dramatically and literally overnight. Over the course of that amazing first day, Peter learns that not only has he acquired perfect vision and muscle tone, but he has also gained greatly increased strength and agility, the ability to fire strands of strong webbing from his wrists, a "spider-sense" which gives him a psychic warning of any danger to himself and the ability to extend a mass of minute barbs from his skin which can allow him to adhere to any smooth surface. While he glories in these new abilities which allow him to fend off bullies like Eugene "Flash" Thompson and jump from rooftop to rooftop with ease, Aunt May and Uncle Ben, who care for him, become concerned for their nephew's new strange and secretive behaviour.
On a trip to the library, Uncle Ben confronts Peter about it and stresses to him that with maturity and power comes great responsibility. Peter impatiently snaps at him and secretly heads off to his true destination, a sports arena that promises a $3000 prize to any man who can stay for 3 minutes in the ring with the wrestler, Bonesaw McGraw. With some difficulty, Peter defeats the wrestler and is cheered as the Amazing Spider-Man. However, Peter is cheated by the fight promoter and in retaliation, does not stop a criminal who has stolen the gate money.
Walking to the library with some satisfaction, he finds that his Uncle has been shot by a carjacker in the street and Ben dies in front of him. Enraged, Peter dons his spider costume to pursue the murderer using his webs for transportation for the first time. He confronts the killer in an abandoned warehouse only to learn to his horror that the killer is the same criminal he could have stopped earlier when he had the chance. The murderer was kicked into a window by Peter, but Peter did not know that he would fall out of the window to his death. Peter is left to kick himself for his selfishness.
Months later after graduation from high school, Peter decides to live up to his Uncle's words, "With great power, comes great responsibility" by becoming a superhero fighting crime all over the city. He eventually learns a way to make it pay by supplying photographs of himself to Daily Bugle publisher, J. Jonah Jameson who has a continual need for Spider-Man photos even though he vilifies the vigilante in his paper.
While this is happening, Norman Osborn has experienced a dramatic transformation himself. To save his company from losing a vital military contract, he subjects himself to a dangerous human test of an experimental performance enhancement chemical. The chemical increases his strength and intelligence, but also drives him insane, creating a new malevolent personality which comes forth to murder any one standing in his way. Using his company's prototype armour, a personal flight device called a glider and a nightmarish green facemask from his collection, Norman lashes out as a figure that is later dubbed the Green Goblin.
Spider-Man and the Goblin eventually meet at the World Unity Festival where the Goblin murders the company board of directors that were planning to fire him. Spider-Man drives the Goblin off and saves Mary Jane as well.
While Peter mourns the fact that he seems to have lost MJ for Harry during all this time; the Goblin tempts him, after abducting him as Spider-Man, to join with him against an ungrateful world that hates him. Spider-Man refuses and the insulted Goblin vowes revenge. This takes on a terrible nature when Norman deduces that Peter is Spider-Man and begins to strike at his loved ones, first Aunt May and MJ. Aunt May gets injured and is forced into the hospital. Harry later discovers that Mary Jane has fallen for Peter Parker, and gets mad.
This leads to a climax on the George Washington Bridge where the Goblin tells Spider-Man to choose whether to save MJ or a cable car of children. Spider-Man, with some help from the New York City population, manages to save both. The Goblin, enraged at being thwarted, brings Spider-Man to an abandoned building.
The Green Goblin promises to torture and kill Mary Jane before dueling with Spider-Man in brutal hand to hand combat. Spider-Man defeats him, only to be begged to stop his attack when the Norman personality regains control. Tearfully, Norman begs Peter to help him control his mental problem, unaware that the Goblin personality is manipulating his body subconciously for a sneak attack on Spider-Man using his glider's remote controls. Peter rejects the overture and barely avoids the charging glider that is hurtling in to spear him in the back, only to fatally impale Norman in the chest instead.
Honoring Norman's request not to tell Harry the truth, Spider-Man brings Norman's body home and Harry becomes convinced that Spider-Man murdered his father. At the funeral, Harry swears revenge on Spider-Man while reaffirming his friendship with Peter. Dismayed at the tragedy he seems to cause to all those close to him, he rejects Mary Jane's words of love to keep her from becoming a potential target of his enemies yet again. The film ends with Peter walking away from MJ, who seems to now suspect that Peter is Spider-Man, while trying making the best of the situation with a de facto victory lap as he swings around the city with ease.
The general critical reaction was enthusiastic with Tobey Maguire being singled for particular praise for his performance. There were complaints about the second hour of the film being rather derivative and the CGI being overused and too obvious.
Some vocal comic book fans aired complaints about the change made in Spider-Man's webs: in the comic books, Peter Parker invented a mechanical web-shooting device; while in the movie he produced his webbing naturally. These complaints were largely dismissed by fans of the movie as fanboy griping. (Similar complaints had been made about the film adaptation of X-Men.)
The general public ignored those complaints and made this film a smash hit grossing $406 million in its theatrical run in the United States alone, and an equally successful home video release. which made Tobey Maguire, previously known as a baby faced character actor into a major star. As of December 2002, Spider-Man remained the highest-grossing film of the year, and one of the ten biggest box office smashes of all time.Critical Reaction