  Number partitioning is one of the classical NP-hard problems of combinatorial
optimization. It has applications in areas like public key encryption and task
scheduling. The random version of number partitioning has an "easy-hard" phase
transition similar to the phase transitions observed in other combinatorial
problems like $k$-SAT. In contrast to most other problems, number partitioning
is simple enough to obtain detailled and rigorous results on the "hard" and
"easy" phase and the transition that separates them. We review the known
results on random integer partitioning, give a very simple derivation of the
phase transition and discuss the algorithmic implications of both phases.
