Until recently, engineering materials could be characterised successfully using relatively simple testing procedures. As materials technology advances, interest is growing in materials possessing complex meso-, micro- and nano-structures, which to a large extent determine their physical properties and behaviour. The purposes of materials modelling are many - optimisation, investigation of failure, simulation of production processes, to name a few. Modelling and characterisation are closely intertwined, increasingly so as the complexity of the material increases. Characterisation, in essence, is the connection between the abstract material model and the real-world behaviour of the material in question. Characterisation of complex materials therefore may require a combination of experimental techniques and computation. This book contains papers from the Fourth International Conference on Computational Methods and Experiments in Materials Characterisation which brought researchers who use computational methods, those who perform experiments, and of course those who do both, in all areas of materials characterisation, to discuss their recent results and ideas, in order to foster the multidisciplinary approach that has become necessary for the study of complex phenomena.