This book is devoted to the measure of non-compactness (essential norm) in weighted Lebesgue spaces for maximal, potential and singular operators dened, generally speaking, on homogeneous groups. The main topics of the monograph contain related results for potential and singular integrals in weighted function spaces with non-standard growth. One of the main characteristic features of the monograph is that the problems are studied in the two-weighted setting and cover the case of non-linear maps, such as, Hardy-Littlewood and fractional maximal functions. Before, these problems were investigated only for the restricted class of kernel operators consisting only of Hardy-type and Riemann-Liouville transforms. The book may be considered as a systematic and detailed analysis of a class of specific integral operators from the boundedness/compactness or non-compactness point of view. The material is self-contained and can be read by those with some background in real and functional analysis.