Samuel Palmer (1805-1881) was one of the leading British landscape painters of the 19th century. Inspired by his mentor, the artist and poet William Blake, Palmer brought a new spiritual intensity to his interpretation of nature, producing works of unprecedented boldness and fervency. Pre-eminent scholar William Vaughan--who organized the Palmer retrospective at the British Museum and The Metropolitan Museum of Art in 2005--draws on unpublished diaries...