Jethro Tull was and still is a unique phenomenon in popular music. Their mix of hard rock, folk melodies, blues licks, surreal, impossibly dense lyrics and overall profundity defied easy analysis, but that didn't dissuade fans from giving them 11 gold and five platinum albums. No record store in the country would want to be without multiple copies of each of their most popular albums (Benefit, Aqualung, Thick as a Brick, Living in the Past), or their various best-of compilations. Of their contemporaries, only Yes could claim a similar degree of success, and Yes endured several major shifts in sound and membership in reaching the 1990s, while Tull remained remarkably stable over the same period.  In 1993, Chrysalis released a four-CD 25th Anniversary Box Set consisting of remixed versions of their hits, live shows from across their history and a handful of new tracks. As co-founded and led by wildman-flautist-guitarist-singer-songwriter Ian Anderson, the group has carved a place all its own in popular music. Jethro Tull continues to perform to big houses when they tour.