Mental Radio: Does it work, and how? (1930) is a book by American author Upton Sinclair, self-published initially. The book documents Sinclair's tests of his second wife, Mary Craig Sinclair's psychic abilities during a period of depression and interest in the occult. Mary attempted to replicate 290 drawings made by her brother, with Sinclair claiming she successfully duplicated 65, had 155 "partial successes", and 70 failures. The experiments lacked a controlled scientific environment.
The German edition of the book included a preface by Albert Einstein, who praised Sinclair's writing. In 1932, psychical researcher Walter Franklin Prince conducted an analysis of the results and believed that telepathy had been demonstrated in Sinclair's data. Prince's analysis was published as "The Sinclair Experiments for Telepathy" in Part I of Bulletin XVI of the Boston Society for Psychical Research in April 1932 and included in the book's addendum.
Sinclair has been criticized for his "credulous" belief in occult and pseudoscience topics. Martin Gardner wrote "As Mental Radio stands, it is a highly unsatisfactory account of conditions surrounding the clairvoyancy tests. Throughout his entire life, Sinclair has been a gullible victim of mediums and psychics." Gardner also pointed out that the possibility of sensory leakage during experiments had not been ruled out:
When Mrs. Sinclair was tested by William McDougall under different conditions, the results were unsatisfactory.