Thread: how to send message to other controller ?

Hi everyone !
I want to send a message I was creat in one Action Controller to display on the view of other controller action. How can I do that?

for example: In books/add action ( action add on books controller ) I have created a message "It's Ok" . then I redirect to librarys/show action ( action show on librarys controller) . I want to get that message to display on the view of this action .

Please help me quick and clearly ! thanks all !