A four-page memo written by Steve Jobs and a functioning Apple I motherboard will be auctioned by Sothebys.com. The auction is set to take place on June 15th in New York City, and Sotheby's estimates the Apple I motherboard, created by Steve Wozniak, could sell for up to $180,000.

Sotheby's claims that this Apple I motherboard is one of only six known to exist in working condition, but its hefty price tag also covers the original operation manual, a BASIC programming guide, and the cassette tape interface. A similar but non-functional Apple I motherboard was auctioned by Christies.com in 2010, and in that instance the motherboard set sold for a grand total of £133,250, or $212,267. The board originally sold for $666.66 in 1976, with the optional cassette interface costing an additional $75.

The Steve Jobs memo is estimated to sell for much less — up to $15,000 — and offers a glimpse at Jobs' early work at Atari. It's addressed to Stephen Bristow, Jobs' supervisor at the time, and includes circuit diagrams and ideas on how to improve Atari's World Cup Football arcade game. Jobs was exploring ways to add variety to the gameplay and increase the unit's replay value to appeal to arcade shop owners. You might not want to call your investment banker just yet, because Sotheby's recently auctioned Apple's founding contract — estimated at $150,000 — for 1.6 million dollars.