When Book magazine made a deal with Barnes & Noble three years ago, its fortunes soared. “Over the next 18 months, circulation of Book rose to 1.2 million from 100,000.” Its ad rates tripled. But the cost of putting out the magazine outstripped its success, and B&N reconsidered the venture. Now the magazine will be relaunched as Barnes & Noble Presents Book and its circulation will be drastically cut to 150,000.