Floor structures account for the majority of all structural material incorporated into a typical building and plate theories provide the information required to design them. This comprehensive book provides a wide-ranging account of the theoretical aspects of plate and slab theory - in essence structural floors - followed by a discussion of the construction and design of real plate and slab elements. The early chapters discuss kinematics and statics, then the theories of elastic and plastic plates and slabs are developed and studied. The novel methods described are capable of providing 'safe' lower bounds on the collapse loads for a wide range of shapes and types of floor. Then follows a discussion of what criteria should be met by a construction method. These criteria are used to develop design principles for what is termed the 'preferred method of construction'. Worked examples and exercises are provided throughout. The final sections include more lengthy exercises, an extensive, annotated bibliography and some brief historical notes on the evolution of the subject.