John Eliot Gardiner goes in search of Bach the man and the musician. The famous portrait of Bach portrays a grumpy 62-year-old man in a wig and formal coat, yet his greatest works were composed 20 years earlier in an almost unrivalled blaze of creativity. We reveal a complex and passionate artist; a warm and convivial family man at the same time a rebellious spirit struggling with the hierarchies of state and church who wrote timeless music that is today known world-wide. Gardiner undertakes a 'Bach Tour' of Germany, and sifts the relatively few clues we have - some newly-found. Most of all, he uses the music to reveal the real Bach.

• John Eliot Gardiner