Proust's Additions: The Making of 'A la recherche du temps perdu'

It has previously not been feasible to study in depth the expansion of Proust's famous novel, A la recherche du temps perdu. In 1913, the novel was to be 1500 pages; by 1922, when Proust died, it was 3000. How did it grow to such proportions? Which characters were always there - which ones sprang from their author's imagination in his very last years? Had Proust always been as interested in certain psychological phenomena as he was to become during the First World War and after? With the pu...