On June 15 at Sotheby’s, an Apple I Computer †the 1976 device that heralded the start of the personal computing revolution †sold for $374,500, more than doubling the high estimate of $180,000.

The exceptionally rare computer is one of only a handful that remains in fully working condition and was a highlight of Sotheby’s sale of books and manuscripts. Before the Apple I, computers were enormous, unwieldy machines that could only be operated by an expert, but this compact model enabled casual users to type on a keyboard and operate basic programs.

Two bidders battled for the device, which eventually sold to an anonymous telephone bidder. Just before the Apple I came across the block, a 1974 report written by Steve Jobs while he was working at Atari sold for $27,500, exceeding the $10/15,000 estimate.

For information, 212-606-7000 or www.sothebys.com .