Who is Pierre Sandoz from The Masterpiece and what is their importance?

Pierre Sandoz is more or less the autobiographical counterpoint of Émile Zola, the author. He is an eternal optimist, and at the beginning he believes that his group of friends will all experience success in their various artistic fields. Every Thursday evening, he hosts a standing dinner at his home, which he shares with his invalid mother. The purpose of these dinners is to discuss the new art, and what each of the guests is doing in his own field.

Claude's forte is writing, and he is determined to write novels that reflect life as it actually is. Unfortunately, he is regularly panned by critics. Sandoz's strength lies in the fact that he refuses to be intimidated by these same critics, and he is diligently working on his magnum opus, a series of books with one continuous story line and theme.