Guest, who wrote My Life in Orange about growing up in a cult, was found by his new wife Jo at their home in north London on Friday.
Friends said he had been listening to Radiohead on his iPod in bed, and that his wife fought to revive him but with no success.
The results of a post-mortem examination will be known next week, with friends saying the most likely cause of death was a heart attack or stroke.
Guest had an unconventional upbringing in communes linked to the Osho religious movement led by the Indian guru Bhagwan Shree Rajneesh after his mother, Anne, converted from Catholicism.
In My Life in Orange, which was published when Guest was just 27 to critical acclaim, he told how his mother's beliefs led her to dye all her clothes orange, rename herself Ma Prem Vismaya and dedicate her life to the obscure religion.
He was given the name Yogesh and moved between communes in Suffolk, Devon, India Germany and Oregon in the United States in a life he described as "somewhere in between Peter Pan and Lord of the Flies".
After his mother turned her back on the cult when he was 11, they moved back to London and struggled to reintegrate back into mainstream society.
Guest dabbled with drink and drugs but eventually sought refuge in writing, producing a second book after his first about virtual communities called Second Lives in 2007. He wrote for newspapers, including The Guardian, The Observer and the Telegraph Magazine, had been interviewed on Richard and Judy and there was talk of a Hollywood film contract for Second Lives.
Barnaby Burch, who grew up with Guest in a commune in Suffolk, said his family were "devastated" by his untimely demise.
Mr Burch, who also goes by his Osho name Majid, said that he last saw Mr Guest for his stag party in Berlin in October and his wedding to Jo at Islington Town Hall the week afterwards. He said his death had come as a "huge shock".
"He was in his mid-30s, had his whole life ahead of him, starting to really make his name in journalism and writing, he had just got married and was really, really happy," he said. "It was a really good time for him and his death is all the more tragic for that. I can only imagine how Jo must be feeling.
"I just remember him as my geeky, gawky friend, and the days of roaming around Hamstead Heath on our bikes, playing computer games, sharing our favourite books. I got to see him blossom and develop into a grown man, but I will always remember him as a nine-year-old boy."
