Mental Radio is newly available as a free audiobook on Youtube:
An excellent brief biography of Mary Craig is found at the Mississippi Writers and Musicians website.
After reading four books by Jack London, I felt compelled to get the two-volume Book of Jack London by his wife Charmian Kittredge London who survived him almost forty years, and a recent biography of her that resolves several outstanding historical puzzles. Eleven books by Upton Sinclair (nine novels, two non-fiction investigations) led me finally to acquire the books of his wife Mary Craig Kimbrough Sinclair, who is featured in Mental Radio as a psychical researcher into telepathy and clairvoyance. Her 1957 autobiography Southern Belle is a captivating narrative of a life of adventures and friendships with many famous writers, reformers, scientists, and politicians. The thirteenth chapter, New Powers of the Human Mind, recounts her work reported in Mental Radio in 1930 and later discussed in Upton’s autobiography of 1962.
Now that the Sun has entered Pisces, I was intending another post about Albert Einstein based on Upton’s including him in his Lanny Budd series of spy novels. But Mary Craig exemplifies so many virtues associated with Aquarius that her non-fiction accounts of the Einsteins deserve to be included in the March update, and she is entitled to this February shout out. They were not personal friends when Albert wrote the introduction, but they became warm personal friends for the rest of their lives.