The present text covers the connections between information and its processing on the one hand
and physics on the other. In the spirit of Rolf Landauer's slogan Information is physical
consequences of physical laws for communication and computation are discussed e.g. the second
law of thermodynamics.In the second part the pessimism of the first part is overcome and new
possibilities offered by the laws of quantum physics for information processing are discussed:
cryptography teleportation dense coding and algorithms such as Grover's. The culmination
point is Shor's miraculous method for efficiently factoring integers.The epilogue is an
extended version of the third author's closing lecture of the seminar Information & Physics (&
Science Sociology) in which Landauer's sentence is contrasted with John Archibald Wheeler's It
from Bit.
