This review article describes the major structural features of layer double hydroxides (LDHs), gives an overview of their synthetic and modification methods as well as the structural characterization possibilities both the generally used and those, which can only be used for specific LDHs. The catalytic use of these materials without calcination, i.e. the layered structure is preserved, are also highlighted. The paper places the authors' works of about the last decade in the framework of recent papers and review articles of this broad field.