Stan Lee, the man behind comic book legends including Spider-Man and the X-Men, has died aged 95.
Lee was the co-creator of Marvel Comics and also responsible for the Hulk, the Fantastic Four, Iron Man and Thor.
The family's attorney confirmed he died after being taken to hospital on Monday.
Mr Lee, who recently fought off a bought of pneumonia, founded Marvel Comics with Jack Kirby in 1961.
Stars who have played Marvel characters, including Robert Downey Jr, Hugh Jackman and Chris Evans paid tributes to Lee, describing him as "a creative genius".
In a statement Marvel called him the "creator, voice and champion" of the company.
"With a heavy heart, we share our deepest condolences with his daughter and brother, and we honor and remember the creator, voice and champion of Marvel," a statement on their website said.
It added: "Marvel and the entire The Walt Disney Company salute the life and career of Stan Lee and offer their undying gratitude for his unmatchable accomplishments within their halls. Every time you open a Marvel comic, Stan will be there."
The Walt Disney Company, which bought Marvel Entertainment in 2009, saluted Mr Lee's "unmatchable" life and career.
"Every time you open a Marvel comic, Stan will be there," it said. "Please join us today in remembering Stan 'The Man' Lee."
Lee was born on December 28, 1922, in Manhattan and grew up with a love of adventure books and Errol Flynn movies.
He started in the entertainment industry in 1939 and created or co-created Black Panther, Spider-Man, X-Men, The Mighty Thor, Iron Man, The Fantastic Four, The Incredible Hulk, Daredevil and Ant-Man among others.
Lee revolutionised comics by introducing human frailties in his superheroes.
As the top writer at Marvel Comics and later as its publisher, he revived the industry in the 1960s by offering the costumes and action craved by younger readers while insisting on sophisticated plots, college-level dialogue, satire, science fiction and even philosophy.
Many of the characters' stories have since been turned into Hollywood films, turning the Marvel brand into a multi-billion dollar business.
Lee was renowned for making brief comical cameos in each of the Marvel universe films.
His wife of 69 years, Joan, died in 2017. He is survived by his daughter Joan Celia.
Following news of his death, tributes from stars and fans poured in online.
Iron Man actor Robert Downey Jr shared a photo of himself with the comic book legend on Instagram, saying: "I owe it all to you... Rest In Peace Stan."
Chris Evans, who played Marvel characters Captain America in several films and Human Torch in Fantastic Four and its sequel, tweeted: "There will never be another Stan Lee.
"He exuded love and kindness and will leave an indelible mark on so, so, so many lives."
Hugh Jackman, who has starred as Wolverine in multiple X-Men films, wrote on Twitter: "We’ve lost a creative genius.
"Stan Lee was a pioneering force in the superhero universe.
"I’m proud to have been a small part of his legacy and to have helped bring one of his characters to life."
Josh Brolin, who plays Thanos in the Avengers films, said Lee ranked alongside authors Dr Seuss and Ray Bradbury.
"That's where it begins and ends with me," he said. "To those of us who have been so deeply affected by the humanity of his imagination, the understanding of reaching beyond our potential and the necessity of tapping into our immeasurable imaginations, we thank you and are forever indebted."
Director Edgar Wright, who was executive producer on the Antman film, said: "Stan Lee, RIP. Thanks for inspiring so many of us to pick up a pen or pencil and put your dreams onto paper. Excelsior!"
Actor and comedian Seth Rogen said Lee made "people who feel different realise they are special", while Millie Bobby Brown posted on Instagram: "You will be missed."