The goalkeeper. They also call him doorman, keeper, goalie, bouncer or netminder, but he could just as well be called martyr, pay-all, penitent or punching bag. They say where he walks, the grass never grows.
— Eduardo Galeano, Soccer in Sun and Shadow
The soccer goalkeeper is one of the most important players on the field – they are the last line of defense and the first line of attack. To play the position well requires special skills and training.

To many coaches, though, soccer goalkeeping techniques and tactics are a mystery. This is especially true at younger age levels, where often coaches have not played much soccer at all, much less played keeper. Even experienced field players and coaches may not have much experience with goalkeeping.

The Goalkeeper Trainer Course, by The Global Council of Sport Science (GCSS) to help soccer coaches coach their goalkeepers. It outlines and demonstrates basic soccer goalkeeping techniques and tactics, and also touches on the psychology of goalkeeping and provides a primer on goalkeeping equipment.