Useful references 
literature and biography

The work of other artists is often irrelevant and I avoid the influence unless one really feels it can help one's own path. However, the way true artists have worked - through personal communication, notes or material in autobiographical or good biographical works - are very interesting to me - particularly where I feel something for the works they have created.

The following are recommended although not necessarily in print. (Try searching on www.ebay.co.uk or www.abebooks.co.uk) All seem to show that the real artists are those who, above all, continue to explore incessantly without preconception or theory, challenge their own work and are not influenced by (or at least, recognise the powerful influence of) the art market. 

Isamu Noguchi: A Sculptor's World; Thames and Hudson (1967) autobiographical writings and images

works linking to sculptor Henri Gaudier Brzeska and his writings to partner Zofia
Savage Messiah (H.S. Ede)
Gaudier Brzeska: An Absolute Case Of Genius (Paul O'Keefe)

Rodin: a biography (Frederic Grunfeld)

The Unknown Matisse (1869-1908) and Matisse the Master - the second volume (both by Hilary Spurling)

Michael Ayrton (Justine Hopkins)

Giovanni Pisano, Sculptor. (With 370 plates of photographs by Ilario Bessi)
MICHAEL AYRTON, & HENRY MOORE see introduction

various biographies of Jacob Epstein (a good late one of Stephen Gardiner)

Drawn from Life - autobiography (John Skeaping)

works by Herman Hesse

Nature Cure and Home Country (both autobiographical in parts)
Richard Mabey