The fascinating letters between Vera Brittain and Winifred Hotlby, written from 1920 to 1935, tell the story of an extraordinary friendship that created a model for a new kind of independent woman, after the First World War.

This is a literary relationship that began when the women met at Somerville, Cambridge and lasted until Winifred's early death at the age of 35. The letters that kept Vera Brittain and Winifred 'continuously together' shows us the inner life of two women who wished to make their mark on the world. They wrote about their ambitions and encouraged and advised each other. But there were also periods when they were literary rivals (Winifred landed a book deal first) and the letters show them negotiating envy and self-doubt. It was at times an uneven relationship: Vera, five years older, married and had two children during this period, and her Testament of Youth became a bestseller, while Winifred remained a single woman with an adventurous spirit that took her travelling and as one of Holtby's characters says in her famous novel, South Riding: 'I am spinster and I am going to spin!' Vera helped Winifred form her ideology - 'You made me' and Winifred shored up Vera, including managing her husband and children (who were devoted to Winifred) and was Vera's intellectual sounding board.

A social history, a portrait of a time between the wars and a dramatic, touching story, it has all the hallmarks of honest female friendship: one not without friction and with its own delicate co-dependency but it was life enhancing and life changing for them both. After Winifred's death Vera said of their letters that they showed 'that loyalty and affection between women - not only unsung but mocked, belittled - is a noble relationship.'