Page from Gibson's diary describing his experience press checking the 'Somnambulist'.

Source: archives of the Center for Creative Photography (Univ of Arizona), I am the fortunate owner of a book, describing the best of these archive, called 'Original Sources'.

'Original Sources' has lots of interesting and rare info, including diary entries, collected pamphlets, letters and paraphernalia that reveal otherwise hidden motives and ideas behind the photographers and their images.