From BBC News
Actor and director Harold Ramis, best known for the films Ghostbusters and Groundhog Day, has died aged 69
But he was also a talented writer and director, whose credits included Caddyshack and Animal House.
"His creativity, compassion, intelligence, humour and spirit will be missed by all who knew and loved him," said his family in a statement.
Billy Crystal, who starred in the director's mobster comedies Analyze This and Analyze That wrote: "Sad to hear my friend Harold Ramis passed away.
"A brilliant, funny, actor and director. A wonderful husband and dad. Big loss to us all."
Iron Man director Jon Favreau added: "No, no, not Harold Ramis. Worked for him years ago. He was the real deal. Growing up, his work changed my life. He will be missed."
"Harold Ramis was a brilliant, shining example for every comedy writer hoping to achieve excellence the field," wrote Family Guy creator Seth McFarlane.
US chat show host Seth Meyers called him "one of the all time greats", while Scrubs actor Zach Braff said: "If you're my age and got into comedy, Harold Ramis was one of the reasons. Life is fast and over too soon."
Born in Chicago to convenience store owners Ruth and Nathan, Ramis studied at Washington University in Missouri and, on graduation, briefly worked in a psychiatric ward.
He started his career as a writer by penning arts stories for his local newspaper and editing Playboy magazine's "party jokes" section.
"It was amazing how many of these jokes were written in pencil on three-ring notebook paper, or came from people who were incarcerated," he told The Chicago Reader. "It was also amazing how many of them dealt with farmers and farm animals.
After leaving the magazine, he joined Chicago's renowned Second City improvised comedy troupe but said he realised his limitations as a performer after encountering John Belushi.
"When I saw how far he was willing to go to get a laugh or to make a point on stage, the language he would use, how physical he was, throwing himself literally off the stage, taking big falls, strangling other actors, I thought: 'I'm never going to be this big.'"
Instead, he played the straight man - acting as a sardonic foil to Bill Murray in the 18-rated army comedy Stripes, and playing the most straitlaced and scientifically-inclined of the Ghostbusters trio.
The film, a global smash in 1984, spawned a sequel in 1989 as well as a long-running cartoon series. A third instalment had been in development for several years.
Ramis acknowledged that the spectral comedy was his most memorable work but took pride in its longevity.
"People love Ghostbusters in a really big way," he said in 2009. "Parents loved it for their kids. Teachers loved it.
The film remains one of the most successful comedy movies of all time, with takings of more than $500m (£300m) adjusted for inflation.
After the sequel, Ramis developed his career behind the camera, directing former Ghostbuster Bill Murray in Groundhog Day and Robert De Niro in Analyze This.
His other films included The Ice Harvest, Bedazzled and prehistoric comedy Year One, his final movie, in 2009.
He said that his time on a psychiatric ward had prepared him for directing Hollywood's elite.
"People laugh when I say that, but it was actually very good training," he told journalist Mike Sacks. "Not just with actors; it was good training for just living in the world.
"It's knowing how to deal with people who might be reacting in a way that's connected to anxiety or grief or fear or rage. As a director, you're dealing with that constantly with actors. But if I were a businessman, I'd probably be applying those same principles to that line of work."
Film producer Brian Grazer once called him "the father of the modern Hollywood comedy", saying his Animal House script was "thoroughly ripped off by the Porky's series" while "Caddyshack was ripped off by Happy Gilmore; Ghostbusters by Men in Black; and Groundhog Day by the Adam Sandler comedy 50 First Dates."
Ramis also inspired a new generation of film-makers, including Judd Apatow, who cast the director in his 2007 comedy Knocked Up.
More recently, he had directed episodes of NBC television's The Office." No matter what I have to say", he once declared, "I'm still trying to say it in comedic form."
He died of autoimmune inflammatory vasculitis, a rare disease that involves swelling of the blood vessels, his agent told the BBC.
The star had been quiet about his illness, which dated back to 2010, but several friends had visited him recently, including Bill Murray, from whom he'd been estranged for years, the Chicago Tribune said.
He is survived by his wife, Erica, sons Julian and Daniel, daughter Violet and two grandchildren.