The autographs sector enjoyed another bumper year in 2011.
The PFC40 Autographs Index, which tracks the price performance of 40 of the most sought after signatures, rose by 5.20% between 2010 and 2011.
Here are our five favourite autograph sales from the past 12 months.
Liz Taylor's first love letters
Love letters written by a 17-year-old Elizabeth Taylor sold for $47,000 at an RR Auction sale in May.
The collection of more than 60 letters written by the much-missed actress to William Pawley, her first of many fiancés, were valued at $25,000 prior to the star's death in March.
"I've never known this kind of love before, it's so perfect and complete - and mature," Taylor wrote in May 1949.
The couple broke off their engagement after just a year.
Jesse James signed photograph
The only known signed photograph of US outlaw Jesse James made $51,240 at a Leslie Hindman Auctioneers sale in April, far surpassing its high-end estimate of $30,000.
Born in Missouri in 1847, James became infamous for his train robberies and bank raids.
James was killed in 1882 by Robert Ford, a member of his gang, for a $10,000 reward.
Steve Jobs signed founding Apple contract
The founding partnership agreement of the Apple Computer Company, signed by Steve Jobs, who died last year, sold for $1.6m at Sotheby's in December.
The 1976 document, also signed by Jobs's partners Steve Wozniak and Ronald G Wayne, had arrived at the auction with a $150,000 high-end estimate. The value of the winning bid is evidence of the popularity of the Apple name with collectors. The company is behind innovations such as the iPhone and iPad.
Tintin cartoons signed by Moonwalkers
A copy of a French version of Tintin on the Moon, autographed with comments by a moonwalker from each of the six successful Apollo moon missions, sold for €100,003 ($132,400) at an Artcurial auction in November.
The comments from the moonwalkers are light hearted in nature. Apollo 11's Buzz Aldrin refers to himself as the "first moonwalker after Tintin", while Apollo 14's Edgar Mitchell claims to have taken the "Longest walk on the moon after Tintin".
In light of the sale, some may consider that our moonwalker autographs on a photograph of Buzz Aldrin's lunar bootprint are underpriced.
The Lost Dauphin
A set of calligraphy exercises written and signed by Prince Louis-Charles of France, known as the 'Lost Dauphin', achieved $30,000 at Spink Smythe in November.
The prince became the prisoner of revolutionaries at the age of just eight, forced to sign claims of his mother Marie Antoinette's guilt and almost certainly killed in custody when aged just 10 in 1795, despite some legends suggesting he made an escape.