When the Norwegian composer Christian Sinding introduced his young friend Frederick Delius (1862-1934) to Edvard Grieg (1843-1907) in Leipzig in 1887, it was to be a memorable occasion for each of them. Delius in particular was later to write of this first meeting with Grieg with great fondness and affection: 'I was very proud of having made his acquaintance, for since I was a little boy I had loved his music. I had as a child always been accustomed to Mozart and Beethoven and when I first heard Grieg it was as if a breath of mountain air had come to me.'

It was, for both men, the beginning of a long and deep personal friendship that, despite the inevitable vissitudes of time, survived until death was to claim each of them. Of all Grieg's English friends, Delius was by far the closest; and Grieg, in turn, played an important role in Delius's development both as a man and a composer. A contributory factor to their friendship was Delius's profound commitment to and interest in Norway even before he met Grieg. Throughout his life he was drawn to Norway's breathtaking landscape, its literature, its art and the character of its people.

Much the larger part of many letters exchanged between Edvard and Nina Grieg and Frederick Delius, usually conducted in German, has remained unpublished until today. Now, for the first time, the entire correspondence, with the fascinating insights which it offers into some extraordinary lives, has been brought together and arranged in chronological order and widely commented upon. Dr Lionel Carley, adviser and archivist to the Delius Trust and author of four books on Delius, has thus created a biographical double portrait. As well as revealing a wealth of opinions and comments upon the music and manners of their contemporaries and a varied discussion of the many problems involved in the labours of composition, Grieg and Delius offer a singular number of glimpses into their deep, and occasionally troubled, emotional lives.

Delius often discussed his affaires de coeur with the Griegs - although probably more with Grieg's wife Nina than with Grieg himself. 'Rattling' was the Griegs' codeword for Delius's affairs and a 'rattlesnake' was the object of his attention; terms that mainly Nina would use in her role as the younger man's confidante and counsellor. Grieg's own complicated romantic life - and the occasionally rocky nature of his marriage to Nina - are also referred to, as is Christian Sinding's apparent preference for married women.

The publication of Grieg and Delius, A Chronicle of Their Friendship in Letters is intended to make a contribution to the growing literature dedicated to a deeper understanding of the music of our age.