Susquehanna University Press has just published The Virtue of Suspense: The Life and Works of Charlotte Armstrong by Rick Cypert, professor of English at Nebraska Wesleyan University and author of America's Agatha Christie: Mignon Good Eberhart, Her Life and Works (2005). (Although the press's catalog lists the Armstrong book as out in December, I learned from the author that it is available now.)
Armstrong (1905–69) is probably best known for the Edgar-winning and Anthony Boucher favorite A Dram of Poison (1956) and The Unsuspected (1946; film 1947). Further details about the biography here.
About the photo: Charlotte Armstrong Lewi, courtesy of Jerry Lewi, the Charlotte Armstrong Family Trust.