The aim of this proposal is a comprehensive structural investigation of a technologically-important perovskite-based ferroelectric material xBiScO3-(1-x)PbTiO3 through studying their pair distribution function (PDF) both at ambient and non-ambient temperatures. In so-doing we aim to elucidate some fundamental disputed issues of ferroelectric solid solutions regarding average structures, short range ordering, nano-domains and thermal evolution of these systems. We propose to use GEM for this study which is a dedicated instrument for PDF investigations for both crystalline and disordered systems.