US online retailer Amazon.com announced Monday it will acquire British online bookstore The Book Depository. The cost of the transaction remains undisclosed. The British company based in Gloucester was expected to chalk up sales of 120 million pounds (135 million euros) for the fiscal year ending in June, according to industry specialist TheBookseller.com. The Book Depository last year had an operating profit of 2.3 million pounds, TheBookseller.com said.