Since he left his native Canada for the US to release his debut album in 1967, Leonard Cohen has become one of the most influential and respected songwriters in the world. Lauded for his poetic lyrics as much as for his enduring, lugubrious melodies (his songs have been recorded in over 2,000 different renditions), his unique contribution to modern music was celebrated last year with his induction into the Rock & Roll Hall of Fame. Today is his 75th birthday and he shows no sign of stopping, with a concert scheduled in Barcelona this evening as part of his phenomenally well-received 2009 world tour.