Looking over some of the 11,000 treasured pieces of paper that have consumed his life for 34 years, Dwight Cleveland readily admits that he is out of the ordinary. "I do believe that there is a genetic aberration among people who are collectors, and I definitely have that," he says with a laugh.
Since he took up his hobby as a 17-year-old high school student, the now 52-year-old Chicago real estate developer has amassed an unrivalled assortment of posters worth $3.5m (£2.1m). Now, however, he has decided enough is enough; by the end of the month he hopes to have a buyer for the largest privately owned mass of film ads in the world.
"There just isn't that much out there that I haven't seen, so it's getting a little stale," he says. "Plus the burden of owning so many posters is becoming overwhelming. There are posters everywhere; stacks and stacks of them. Even though everything is catalogued and databased, it is still too heavy for my shoulders."
Mr Cleveland was not a movie buff when his eyes first lit up at the sight of a poster. It was, he explains, the art work that first attracted him.
"The art teacher at my high school was a collector of these posters, and we all made fun of him because of his crazy hobby. Once, the home of a poster dealer in Boston burned down and he went down there in the middle of the night to go through the rubble and salvage some posters. He brought some back to show us, cradling them like a little baby because he was very proud of this hunt, and one of them was a lobby card for a film called Wolf Song from 1927 starring Gary Cooper. It had an art deco design that was very striking... I felt I had to own that poster."
Anything can become collectable, as long as there is someone out there willing to hunt it down and hoard it, but for Mr Cleveland movie posters are the best items a fanatic could wish to be obsessed by.
"The stuff is so damn difficult to find, it's a lot harder than baseball cards or comic books, because those were manufactured and advertised and distributed so you could go out and buy them – the question was just who could save them in a condition that was worthwhile?
"Movie posters were only distributed to cinema owners, and the old ones would either get pasted over by the next week's posters, or the guy who pushed the broom around would be instructed to take them down and throw them out. So not only were they in low distribution to begin with, but their chances of survival over decades would be pretty remote even in normal circumstances. In World War I and World War II, they would go into theatres and cinemas and take away posters for recycling, so stuff from the 1920s and 1930s is particularly rare."
His purchases have included a 1933 King Kong poster from Sweden for $25,000 – the most valuable item in his collection and now, he says worth double that figure – and 48 separate designs for Chinatown ads. The internet has helped him hugely, but he has also been as far afield as Auckland, Vienna, Paris, Cairo and Havana in search of elusive finds.
"I've been to flea markets on pretty much every continent, turning up at 5.30 in the morning with my flashlight, checking things out while people are unloading them from the back of a truck. I love that aspect of collecting."
Though his wife and three children will probably be glad for him to go into collecting retirement, it is uncertain if he has fully come to terms with the scale of what he is giving up – he bought another poster just last week. But with less than a month to go and still no buyer found, it might just be that his collection carries on growing for a little while longer yet.