Book: The Nature of Light - to order click sales & info "The Nature of Light," Christensen's second book, is produced in large format with (156) pages printed on fine paper imported from Germany. The book features (38) full page color plates of large studio paintings and (100) reproductions of plein air field studies. Essay by Todd Wilkinson and notes on painting in Christensen's own words help readers understand Christensen's philosophy about his craft.