The four new chapters added to the second enlarged edition have been chosen with the object of stimulating interest among those concerned for initiating further development of thin shells on these lines. In Chapter 23 a state of the art survey of finite element analysis applied to thin shells is presented. The possibilities that thin shells offer for building intermediate floors are examined in Chapter 24 with the aid of a fully worked example. Shell foundations have been used to a limited extent in the past for individual footings. The use of shell rafts and the assessment relative merits of different shell forms for this purpose are still to be fully explored. Those interested in this subject will find Chapter 25 to be of special interest. One of the obvious infirmities of concrete is its notoriously low tensile strength. For this reason the effort in the past has been to design concrete shells as compression forms. Ferro cement hailed sometimes as super reinforced concrete liberates us from this restriction because of its higher tensile strength and ductility. It opens the door to the imaginative use of tension forms. Some of these possibilities are briefly explored in the concluding chapter by means of examples.