No, the process dictionary is not a mutable variable - there is no natural idiom to use values stored in the process dictionary as variables in code, you have t

No, the process dictionary is not a mutable variable - there is no natural idiom to use values stored in the process dictionary as variables in code, you have to get them out and put them in via immutable variables. Any given Erlang process has meta-information about itself, how many reductions it has, how big its heap is, which flags are set. These are the global state of the process. The process dictionary allows you to store and manipulate your own global state of the process - and the people (hands up, that includes me) get smart and use it as local state of the programme and then get their bum bitten badly and swear never to dance with the dark side again... :( Not bitter :)