Benjamin Schumacher

Contrast Shannon's code- and communication-based approach to information with a new, algorithmic way of thinking about the problem in terms of descriptions and computations. See how this idea relates to Alan Turing's theoretical universal computing machine, which underlies the operation of all digital computers.

What are the laws governing quantum information? Charles Bennett has proposed basic rules governing the relationships between different sorts of information. You investigate his four laws, including quantum teleportation, in which entanglement can be used to send quantum information instantaneously.

What is information? Explore the surprising answer of American mathematician Claude Shannon, who concluded that information is the ability to distinguish reliably among possible alternatives. Consider why this idea was so revolutionary, and see how it led to the concept of the bit-the basic unit of information.

The science of information is also the science of secrets. Investigate the history of cryptography starting with the simple cipher used by Julius Caesar. See how entropy is a useful measure of the security of an encryption key, and follow the deciphering strategies that cracked early codes.

Intuition says we measure information by looking at the length of a message. But Shannon's information theory starts with something more fundamental: how surprising is the message? Through illuminating examples, discover that entropy provides a measure of the average surprise.

Probe the link between entropy and coding. In the process, encounter Shannon's first fundamental theorem, which specifies how far information can be squeezed in a binary code, serving as the basis for data compression. See how this works with a text such as Conan Doyle's The Return of Sherlock Holmes.

Algorithmic information is plagued by a strange impossibility that shakes the very foundations of logic and mathematics. Investigate this drama in four acts, starting with a famous conundrum called the Berry Paradox and including Turing's surprising proof that no single computer program can determine whether other programs will ever halt.

Maxwell's demon has startling implications for the push toward ever-faster computers. Probe the connection between the second law of thermodynamics and the erasure of information, which turns out to be a practical barrier to computer processing speed. Learn how computer scientists deal with the demon.

You focus on the Einstein-Bohr debate, which pitted Einstein's belief that quantum events can, in principle, be known in every detail, against Bohr's philosophy of complementarity - the view that a measurement of one quantum variable precludes a different variable from ever being known.

Learn how DNA and RNA serve as the digital medium for genetic information. Also see how shared features of different life forms allow us to trace our origins back to an organism known as LUCA-the last universal common ancestor-which lived 3.5 to 4 billion years ago.