** 1/2 “ISLE OF NOISE” By Mark J. Prendergast; <i> St. Martin’s Press ($15.95)</i> : <i> Items in this periodic survey of pop-related books, videocassettes and laser discs are rated on a scale of one star (poor) to five (a classic). </i>

More than you need to know about blues-rocker Rory Gallagher and less than you’d like to know about Sinead O’Connor: Though updated from the 1987 “Irish Rock” for American publication, this detailed guide seems out of date and parochial considering the worldwide impact of O’Connor, who only gets a brief mention, though her picture is on the cover. What’s more, a deserved dissertation on Van Morrison suffers from Prendergast’s labored critical analyses. Still, sections on the early beat groups and Irish folk-rock are fascinating accounts of pop musical evolution outside the more familiar Britain/U.S. breeding grounds, while the “Modern Music” chapter does a good job showing the cultural/musical context that launched U2.