Kevin Federline and Britney Spears are once again making headlines, and have been for a while now, with the release of his book about their embattled lives back in the day. In his memoir You Thought You Knew, Federline opens up about one of the darkest, most heartbreaking moments in the pop icon's life: an intervention arranged by a "frightened" Lynne Spears as her daughter's life spiraled out of control. For years, fans have speculated about what really went on behind closed doors as Britney's world unraveled in the mid-2000s.