1.2. History of Counterpoise Correction. We consider the historical record in an effort to understand the emergence of a conventional wisdom that the Boys-Bernardi procedure "overcorrects" for BSSE. Evidence debunking that viewpoint had appeared already in reviews dating to the late 1980s and early 1990s, nevertheless this sentiment persists in more recent literature. Very early literature on the efficacy of CP correction is muddled by the use of low-quality basis sets, for which both BSSE and BSIE are sizable. It is difficult to take seriously the early criticisms of CP correction based on minimal-basis calculations, where BSSE can be so large as to convert repulsive interaction into attractive ones. There was also an early suggestion 66 that the Boys-Bernardi procedure erroneously allows the occupied orbitals of one monomer to occupy regions of space that should be taken up by occupied orbitals of the partner monomer in the supramolecular complex, thus causing the CP procedure to underestimate the true interaction energy. This view was later shown to be false, however. In fact, spatial restriction of the occupied orbitals upon formation of the A• • • B complex lies at the heart of the Pauli exclusion principle! The erratic nature of BSSE in small basis sets partly motivated the development of intermolecular perturbation theory in the 1970s, because this approach is inherently free of BSSE. Gaussian basis sets had become more systematized by the 1980s, and a 1988 review observes that it is "generally accepted" that the CP correction brings Hartree-Fock interaction energies closer to the CBS limit, except in the case of minimal basis sets. However, the effectiveness of the CP procedure was questioned in a 1985 study by Schwenke and Truhlar, who performed calculations on (HF) 2 using 34 different Pople-style basis sets and found no systematic improvement when CP was used. That said, there was little variation amongst the basis sets tested and a subsequent study of alanine dimer using many of the same basis sets reached the opposite conclusion, namely, that CP correction typically improves the results. Other work from the same time period suggested that the CP procedure actually insulates the results from otherwise erratic changes in ∆E int upon relatively small changes in the basis set. This understanding was summarized in a 1994 review of the "overcorrection debate". The Boys-Bernardi pro-cedure is not only compatible with the Pauli principle, but furthermore CP-corrected supramolecular calculations afford results of comparable accuracy to intermolecular perturbation theories that are inherently free of BSSE. (In fact, supramolecular perturbation theory calculations may afford non-sensical results for energy components if these are not corrected for BSSE. ) Similarly, comparison of CP-corrected MP2 to the corresponding "chemical Hamiltonian" version of that method, which is inherently free of BSSE, results in excellent agreement for basis sets of moderate quality. By late 1990s (but arguably much earlier than that), it was therefore evident that CP correction generally improves the quality supramolecular interaction energies. Where exceptions can be found in older literature, they are almost always attributable to the use of low-quality basis sets. Nevertheless, reviews by van Lenthe et al. in 1987, and by the same authors again in 1994, bemoan the persistent and widespread belief that the Boys-Bernardi procedure "overcorrects", as well as the notion that the CP correction is merely an "estimate" of the BSSE rather than a well-defined procedure that recognizes the origin of the problem (namely, imbalance in the supramolecular formula of eq. 1) and eliminates it, essentially by definition.