Sliding doors (or sliding patio doors) are typically two panel systems in which the doors sit on rollers that are parallel to the wall, thus allowing the doors to slide in the same plane.
Sliding doors are best utilized in areas filled with furniture where a swing door would create a hindrance, as in a bedroom. The trade off in this case is that only one of the sliding panels can be open at a time, versus a swing door, where both panels can be open simultaneously. This is why large living areas, such as kitchens and family rooms, trend more toward swing doors, while sliding doors are geared more towards private entrances.
Sliding doors tend to fall on the more contemporary end of the design spectrum in comparison to swinging doors, and have become increasingly popular in recent years.
