Two years after making the decision to build infrastructure in Britain, Lightning Source has brought on as a retailing partner. Lightning touts Oxford University Press and Cambridge University Press as two of its biggest publishing partners, so, in the words of Lightning head Ed Marino, it made sense to expand across the Atlantic.

"You've got a public that is very literate and very keen on the type of content we have," said Marino from London, where he was attending the London Book Fair. "Because of the nature of the market, they've become very accustomed to short-run books."

Lightning's U.K. warehouse in Milton Keynes is equipped to print and ship thousands of orders to so that customers have them in as little as 48 hours. Readers benefit from the partnership, Marino said, because Amazon can go directly to Lightning instead of going to a wholesaler, as other retailers must do.

Until now, Lightning U.K. has had relatively few partnerships; one of its most sizable agreements has been with niche site 1st Books ( Marino hedged on whether the Amazon deal would open the door to other such agreements. "Amazon was the big one," he said. "We're going to go with them and then see how the market takes shape."