The most important and extensive collection of letters from author Samuel Beckett will sell through Sotheby's on July 15 in London, as one of the highlights of its English Literature sale.

Beckett's letter trace the history of his theatrical career, as well as his personal life

The 347 letters, many of which are autographed "Sam" and written in French, are valued at £80,000-120,000 ($137,257-205,885). English translations have been provided, with the letters mounted in four folio albums.

The letters are addressed to Beckett's close friends Henri and Josette Hayden, a couple of painters whom he met while they were hiding from the Gestapo in the Vichy, France.

Sharing a love of painting, Beckett and Henri Hayden became close, with some saying that their friendship inspired Vladimir and Estragon in Waiting for Godot.

The letters include details of almost all of Samuel Beckett's theatrical career, with the writer discussing his anxiety and pessimism about his work. Such is their depth, they were used by James Knowlson for his biography, The Life of Samuel Beckett (1996).

While occasional quotes appear in the book, much of the collection remains unpublished, making the sale a brilliant opportunity for scholars of Beckett's work.

While always a celebrated writer, Beckett has seen a surge of popularity among collectors recently, with the manuscript for his first novel, Murphy, selling for $1.4m at Sotheby's in July 2013.

The lead lot of the sale is William Caxton's translation of The Recuyell of the Histories of Troye, the first book printed in English, which is valued at up to $1.3m.

Paul Fraser Collectibles has signed books and collectibles from top authors, including Sir Arthur Conan Doyle, Virginia Woolf and William Golding.