This book imbibes the experimental results on the interaction of charged particles with the material medium undergoing phase transition in terms of energy loss (EL) measurements for both light and heavy particles. The EL was measured in two different classes of ferroelectrics (BT displacive and TGS order-disorder) with a view to understanding the role of unit cell dipole moment and that of the mechanism of dielectric polarisation in a ferroelectric on the critical energy loss. Computer coding is programmed using python and other computer simulation programs like SRIM, PSTAR, and ASTAR, available as FOSS is used. The EL mechanisms with an estimation of the transverse electric field and localized temperature due to the passage of energetic particles obtained using the thermal spike model are used to develop qualitatively a possible model for the observed variation in EL. The EL of energetic electrons was considered to bring out the range dependence of the effect of order at a shortrange on the energy loss.