Michelle Paver is sparkier and less diffident than I recall. We originally met in 2004, when Wolf Brother, the first of her bestselling series of children's novels about stone-age life, appeared. Outcast, number four of a planned six, is published this week, and Paver is becoming used to the trappings of celebrity - interviews, book signings, author tours. She is at home now in the media age as well as the stone age.