4.1 Possible sources
Problem reports
Helpdesk and support team
Trainers and consultants
Customer suggestions and complaints
Improvements made by users
Unintended uses
Comparable products
Old designs and specifications
Badly written contracts
4.2 Getting requirement for mass-market products
The vital role of the marketing department
Turning market reports into requirements
4.3 User requirements in subsystem projects
Subsystems inherit requirements, adding a few of their own