Masonry is a traditional, highly durable mode of construction; many heritage masonry structures, built at various historical periods, have survived, to a lesser or greater extent, adverse environmental conditions, which have reduced, sometimes considerably, their integrity, strength and durability. Due to the cultural significance of heritage architecture, resources are today allocated towards their restoration and conservation. This volume comprises distinguished contributions from the Transactions of the Wessex Institute describing research efforts towards achieving these objectives. Topics covered include: Understanding of constituent materials, modes of construction and overall mechanical behaviour; Dynamic behaviour; Sonic pulse velocity tests; Micro-vibration measurements; Failure mechanisms; Structural strength assessment; Binding material mixtures; Composition and properties of ancient mortars; Contemporary repair material; Infra-red thermography measurements; Mortars, plasters, renders and grouts. The various issues mentioned above are addressed by the present collection of scientific papers with considerable insight and thoroughness. It is thus hoped that this volume will fill a gap in the literature as a valuable source of information and guidance to researchers and engineers working in the area of restoration and conservation of heritage masonry structures.