A book written by a journalist and biographer who two years ago predicted that Sen. John Kerry would win the Democratic presidential nomination, and then watched from inside the Kerry campaign as it soared from near-disaster to triumph, was signed at Riverhead. Publisher Julie Grau signed world rights in the book directly with author Paul Alexander, a former Time reporter who has also been a radio talk show host and directed a documentary on Kerry's Vietnam War experience. Grau, who said she agreed with Alexander that there was a need for an immediate insider's book that will show how the Kerry campaign is likely to shape up against that of George Bush, will publish in late July, at the start of the Democratic National Convention that is expected to crown Kerry as the candidate.