Back to the shelves - the secret of successful shelf putting up is matching the fitting to the wall type, and preferably having the best wall. If you choose a stone or brick wall, and match that with nice 2" masonry screws, then the battle is half won! If you are hoping to store a shelfload of heavy books on a lathe and plaster, or plasterboard, partition - think again! You might be lucky and find some solid wood in there though. A light shelf may be mounted on plasterboard using specialist plasterboard fittings. I have found most success with the chunky metal self-tapping plugs. The kind that deform on the dark side of the plasterboard and supposedly clamp onto it, not so good...