This book describes the analytical formulation and numerical implementation of the three-dimensional dual boundary element method (DBEM) for the thermoelastic analysis of mixed-mode crack problems in linear elastic fracture mechanics. The DBEM overcomes the problem of the singular matrix that is inherent to crack modelling by incorporating two pairs of independent boundary integral equations, namely the temperature and displacement, and the flux and traction equations. One pair is applied on one crack face and the other pair to the opposite one. The temperature and displacement equations are applied on non-crack boundaries.