In 1957, I was invited to give a paper to a symposium of the Society for Experimental Biology in London. This gave me the opportunity to sort out and write down my ideas, most of which had been formulated earlier. What the structure of DNA suggested was that the sequence of bases in the DNA coded for the sequence of amino acids in the corresponding protein. In the paper, I called this the sequence hypothesis. The other theoretical idea I proposed was of a rather different character. I suggested that once information has passed into protein, it cannot get out again. Adding that information means here the precise determination of sequence, either of bases in the nucleic acid or of amino acid residues in the protein. I called this idea the central dogma for two reasons, I suspect. I had already used the obvious word hypothesis in the sequence hypothesis, and in addition I wanted to suggest that this new assumption was more central and more powerful. I did remark that their speculative nature was emphasized by their names. As it turned out, the use of the word dogma caused almost more trouble than it was worth. Many years later, Jacques Monault pointed out to me that I did not appear to understand the correct use of the word dogma, which is a belief that cannot be doubted. I did apprehend this in a vague sort of way, but since I thought that all religious beliefs were without any serious foundation, I used the word in a way I myself thought about it, not as most of the rest of the world does, and simply applied it to a grand hypothesis that, however plausible, and little direct experimental support.