Security concerns nearly canceled the July 7 Live Earth concert in Rio de Janeiro, Brazil. So Lenny Kravitz fans around the world no doubt breathed sighs of relief when the soulful rock star took the stage. Others, meanwhile, were scratching their heads: Where on our greenhouse-ravaged planet has the 43-year-old Kravitz been for the past three years? For one thing, he was recording his take on John Lennon's ''Cold Turkey,'' found on last month's charity release Instant Karma: The Amnesty International Campaign to Save Darfur. (''I used to cover the song back on my first tour,'' says Kravitz. ''I love the groove, how [Lennon] expressed the pain.'') But the biggest chunk of his time was spent in his Miami and Bahamas studios working on a double-disc album, his first since 2004's tepidly received Baptism. ''This one's all over the place,'' notes Kravitz, adding that he hopes to release it by the end of the year. ''It's rock & roll, it's funk. It's slow, it's fast. It's hard, it's soft.'' Whew! Anything else? ''There's jazz. There's reggae.'' At least one thing remains constant: Kravitz's Age of Aquarius idealism. ''The title of the new album,'' he says, ''is It Is Time for a Love Revolution.''