Nicky Haslam, Ruth Brooks, Kieran Holmes, Nitin Sawhney

Libby Purves meets amateur scientist Ruth Brooks; interior designer Nicky Haslam; tax adviser Kieran Holmes and composer and producer Nitin Sawhney.

Ruth Brooks is a former teacher turned amateur scientist. In 2010 she won Radio 4's So You Want to be a Scientist competition with her quest to discover whether snails have a homing instinct. Her book A Slow Passion: Snails, My Garden and Me tells of her scientific journey. A Slow Passion - Snails, My Garden and Me is published by Bloomsbury.

Nicky Haslam is an interior designer whose clients have included Mick Jagger; Rupert Everett and Lord Andrew Lloyd-Webber. His new book Folly de Grandeur celebrates his country home, a former Tudor hunting lodge in Hampshire. Folly de Grandeur - Romance and Revival in an English Country House is published by Jacqui Small Books.

Kieran Holmes is an Irish tax adviser who currently heads Burundi's revenue authority - the Office Burundais des Recettes. Since his appointment in 2010 he has tackled the country's corrupt tax system and helped it move towards greater economic self-sufficiency. He has also worked in Lesotho, Yemen and Swaziland.

Nitin Sawhney is a producer, composer, DJ and multi-instrumentalist. A Mercury Music Prize nominee and MOBO winner, he has collaborated with a range of musicians including Sting; Paul McCartney; Taio Cruz and Anoushka Shankar. His Radio 2 series, Nitin Sawhney Spins the Globe, celebrates sounds from around the world.

Producer: Paula McGinley.