Abstract: Just as fitted sheets provide structure to the lower bed sheet, pocket sheets give structure to the upper bed sheet. To provide a hygienic shield between a duvet and a sleeping person, the upper bed sheet is customarily folded back over the duvet at the head end. The pocket sheet fixes this folded portion in place by fastening together the side hems, either permanently by sewing or releasably using press buttons, thus forming a pocket structure to house the duvet's head end and prevent the sheet and duvet from separating when tossed about by the sleeping person. The pocket sheet is convertible into a simplified duvet cover by attaching a separate matched-size cover sheet using releasable fasteners at their side hems. The bed maker places the cover sheet over the duvet and tucks both into the pocket, then fastens cover sheet to pocket sheet to hold the duvet securely.