A timely Christmas gift from the greatest of all novelists

Over the past few months, I've been enthralled by an obsessive-compulsive little Belgian with a natty moustache who walks like a penguin and solves the most complicated murders. The wit and quirkiness of Hercule Poirot is timeless.

His creator, the late Agatha Christie, is the best selling novelist of all time. Her 80 whodunnits, – most of which star Poirot – sold between two and four billion copies, right alongside William Shakespeare. American Harold Robbins is a distant third at 750m.

There is much to learn from Dame Agatha, who died in 1976 aged 85. Her stories always deliver an entertaining workout for the brain, accompanied by the guaranteed relief of a solution at the end. If you haven't yet discovered her genius, treat yourself to The Murder of Roger Ackroyd and get ready for a lengthy but very enjoyable journey.

While her books have been treasured companions to millions for almost a century, perhaps Ms Christie's greatest gift is to remind us of the value of persistence. Despite her obvious brilliance, the world's best-selling novelist was turned down six times before a publisher finally gave her a break. She never stopped believing in herself. Neither should you. Merry Christmas.