a hybrid binder - folder utilizing a foldable ring system for holding pages , which affords the advantage of easy page manipulation of ring binders with the advantage of flat folding of folders . the binder - folder has two side members which are mutually foldable along the centerline therebetween . two , three or more foldable rings of flat , thin cross - section and of substantially semicircular shape are connected with the side members adjacent with and transverse to the centerline . when the two side members are mutually folded closed , the foldable rings fold along three folds : adjacent each connection with the two side members and at the ring apex . as a result of this foldability feature , the foldable rings are able to flatly fold , thereby permitting the binder - folder to be substantially flat when closed . when the side members are folded open , the rings unfold along the three folds to become substantially semicircularly shaped rings for guiding pages trapped on the foldable rings in the manner of a conventional ring binder . removal and insertion of pages with respect to the foldable rings is achieved by a ring connection mechanism which is releasable with respect to one or both of the side members of the binder - folder , or else the foldable rings may be structured to be selectively openable at other than the ring apex .