So trust this book. Understand that what is told here happened exactly as it has been told. Don’t think that maybe there was a slight slip, or that there is a careless word. I remember in the course of the years some learned psychologist suggesting that maybe Craig had unconsciously got some idea of what the drawings were by seeing the movement of my pen or pencil. This meant just one thing—the learned gentleman didn’t want to believe, and hadn’t taken the trouble to go back and study the book. You who are going to read now will note again and again that I went into another room to make the drawing, and I shut the door. Make note now and bear it in mind all through the book, I never made a drawing in the same room with Craig; and always the door was shut. To have done otherwise would have been to waste her time as well as mine, and she saw to it that I did not waste either. She wanted to _know_; she was _determined_ to _know_; she laid down the law, and I obeyed it. The only way you can reject the evidence in this book is to decide that we were a pair of unconscionable rascals. I’ll give you one opinion about that. Albert Einstein, possessor of one of the greatest modern brains, and also of a high character, was one of our close friends. He came to our home, and we came to his, and he witnessed some of our experiments. When this book was ready for publication in 1929 I sent him a set of the proofs and asked him if he would care to write a preface for the German edition. He consented and wrote the letter in German to the German publisher. Unfortunately, the publisher went out of business. What you are going to read is the exact text of Craig’s book as it was written in the year 1929 and published in the next year. The only changes I have made have to do with the lapse of thirty years since the text was written. Near the end are one or two references to friends who have since died, but you probably never knew those persons, so it doesn’t matter. At the end of the book I have published a few comments on it, and an account, written by myself, of later experiments. Also I give an extensive summary of the results of a study of the drawings published by Dr. Walter Franklin Prince, a Boston clergyman who resigned from his pulpit in order to become Research Officer of the Boston Society for Psychic Research. Dr. Prince asked if we would be willing to entrust the documents to his examination, and I immediately bundled them up and sent them to him by registered mail. The long commentary which he wrote appeared in the _Bulletin_ of the society for April, 1932. Perhaps the most important single item concerning _Mental Radio_ is the following: