Product software vendors are regularly challenged with
identifying and selecting the requirements of upcoming
product releases. Companies struggle to involve their customers and have a hard time selecting the right requirements from the enormous number of candidate requirments. This paper presents a practical approach to overcome these problems by including customers in the requirements management process through different types of involvement. The presented case illustrates how software requirements are gathered from customers, by involving them
on three different levels. Based on the industrial experiences we present six lessons from customer involvement in
large scale requirements management.