Miss Pim's Camouflage
Author: first_name: Dorothy
last_name: Tennant
Language: English
Year: 1918

Mid-WWI, staid Englishwoman Miss Perdita Pim suffers a sunstroke gardening & gains the power of invisibility.  She becomes a super-secret agent, going behind German lines, sometimes visible, sometimes not, witnessing atrocities & gleaning valuable war information. (Summary by Grant Hurlock)