[1] The German edition included a preface written by Albert Einstein who admired the book and praised Sinclair's writing abilities.

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 was included in the addendum for the book.

[4] Martin Gardner wrote "As Mental Radio stands, it is a highly unsatisfactory account of conditions surrounding the clairvoyancy tests.

"[1] Gardner also wrote the possibility of sensory leakage during the experiment had not been ruled out: In the first place, an intuitive wife, who knows her husband intimately, may be able to guess with a fair degree of accuracy what he is likely to draw—particularly if the picture is related to some freshly recalled event the two experienced in common.

Also, one must not rule out the possibility that in many tests, made across the width of a room, Mrs. Sinclair may have seen the wiggling of the top of a pencil, or arm movements, which would convey to her unconscious a rough notion of the drawing.