The youngest surviving son of Johann Sebastian Bach, John Christian (born Johann, he adopted the English form of his name in maturity) represents a unique link between the baroque and classical worlds. His early musical training was with his father, but his own musical preferences led him to Italy and study with Padre Martini. He abandoned the Lutheranism of his youth, becoming a Roman Catholic and composing much sacred music as organist of Milan Cathedral.

He turned next to opera, and quickly made a reputation that led to an invitation to become composer to the King's Theatre in London, and then music master to the Queen. In that role, and as impresario of the famous Bach-Abel Concerts, he was the leading figure in London's musical world. Gainsborough painted his portrait; the French philosopher Diderot was an acquaintance.

. He became Mozart's friend and mentor, having met him when the child prodigy visited London in 1764. Mozart thought highly of his piano sonatas, arranging some of them as concertos, and scholars have discovered many "Christian quotes" in Mozart works ranging from the symphonies to The Magic Flute. On hearing the news of his death, Mozart wrote to his father, "Have you heard that the English Bach has died? What a loss for the world of music!".

During his lifetime he was the most successful of the musical Bachs, although he died deeply in debt, and until quite recent years his music has been largely ignored. This impeccably researched biography of the man and his times is evidence that his true stature is now being recognized.