Richard P. Feynman, December 1959, “I will not now discuss how we are going to do it, but only what is possible in principle—in other words, what is possible according to the laws of physics... I am telling you what could be done if the laws are what we think; Let us represent a dot by a small spot of one metal, the next dash, by an adjacent spot of another metal, and so on. Suppose, to be conservative, that a bit of information is going to require a little cube of atoms. Perhaps we need a hundred and some odd atoms to make sure that the information is not lost through dilution, or through some other process. I have estimated how many times letters there are in the Encyclopedia, and I have assumed that each of my 24 million books is as big as an Encyclopedia volume, and have calculated, then, how many bits of information there are (10^15). For each bit I allow 100 atoms. And it turns out that all of the information that a man has carefully accumulated in all the books in the world can be written in this form in a cube of material one two-hundredth of an inch wide, which is the barest piece of dust that can be made out by the human eye.”