  Cadabra is a new computer algebra system designed specifically for the
solution of problems encountered in field theory. It has extensive
functionality for tensor polynomial simplification taking care of Bianchi and
Schouten identities, for fermions and anti-commuting variables, Clifford
algebras and Fierz transformations, implicit coordinate dependence, multiple
index types and many other field theory related concepts. The input format is a
subset of TeX and thus easy to learn. Both a command-line and a graphical
interface are available. The present paper is an introduction to the program
using several concrete problems from gravity, supergravity and quantum field
theory.
