Apple Is are rare. Around 200 units were originally produced and it is estimated that fewer than fifty are still in existence. One with the serial number 22 is to be included in a Christie's sale on October 9, 2012.

The Apple I was the original Apple computer and was sold as a pre-assembled motherboard without a casing, power supply or keyboard. A TV would be used in place of a monitor.

It was designed and hand-built by Steve Wozniak with improvements suggest by Steve Jobs, who handled sales and marketing. The units were priced at $666.66 and were famously dispatched direct from the garage of Steve Jobs' parent' house.

The previous Apple I sold by Christie's, in November 2010, fetched £133,250/$212,267. It was exceptional in having a signed letter from Steve Jobs and its original box and instruction manuals and was acquired by Marco Boglione, a private Italian collector. Steve Wozniak attended the auction in person.

Unit 22, pictured above, has come from the estate of Joe Copson, a former Apple employee and is expected to fetch between £50,000 and £80,000.

The eCatalogue for the sale in which is is to be included, TRAVEL, SCIENCE AND NATURAL HISTORY including the Polar Sale to commemorate the Scott Centenary, 1912-2012 will shortly be online at www.christies.com/calendar.