This "absolute localization" makes use of the Huzinaga-type projection operator, for which the effect of using a heavily truncated basis is much less severe than for the levelshift projection operator. Another crucial ingredient is the correction of the WF-in-DFT energy thus obtained by the difference between a KS-DFT supersystem energy and the corresponding DFT-in-DFT embedding energy based on absolute localization. The latter correction is intended to mitigate effects at the boundary region between subsystems, especially when cutting through covalent bonds. The approach has been combined with various wavefunction schemes such as CCSD(T), CASPT(2) , and a variant of full configuration interaction quantum Monte Carlo . Recently, it has also been combined