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This review has shown that recent studies reputed to establish new concepts about the chemical structure of petroleum and its physical interactions may be premature. The concept that asphaltenes have average molecular weight of the order of 700 does not explain why only a minor fraction of asphaltenes evaporate during refinery processing at 500 °C under a high flow of steam and these evaporated asphaltenes have a molecular weight of the order of 700. In contrast to several recent results, the overwhelming evidence is that resins solubilize asphaltenes by more than just acting as a solvent. Although the resin-asphaltene interaction is not a specific interaction, like hydrogen bonding, it is likely an interaction between large, flat polynuclear aromatics through dispersion forces. While the use of solubility parameters and the regular Flory-Huggins model are only rough approximations when applied to predict the solubility of low molecular weight and polymer systems, they provide good approximations when applied to petroleum systems. The volume average mixing rule for solubility parameters provides the basis for the oil compatibility model that successfully predicts the compatibility operating window for mixtures of oils from data only on the component oils. This model also enables predicting the solubility of an oil in mixtures of cyclohexane and n-heptane and in chlorobenzene and n-heptane based upon data of that oil in toluene and n-heptane. The regular Flory-Huggins model correctly predicts that the volume of normal paraffin at the flocculation point for a crude oil has a maximum when plotted against the normal paraffin carbon number but at high dilutions in the normal paraffin; the amount of asphaltenes precipitated decreases with increasing normal paraffin carbon number. The slow rate of precipitation of asphaltenes is a legitimate concern for both oil flocculation tests and applications of the Oil Compatibility Model. Fortunately, the errors introduced are greatest for nearly incompatible oils that at worst only cause a slow rate of fouling. This effect previously was attributed to the adsorption of asphaltenes on hot surfaces. The objective for applications to live oils is to use only experiments on the dead oil at ambient conditions to predict asphaltene solubility of the live oil at reservoir conditions. This has been successfully accomplished using either the regular Flory-Huggins equation or the PC SAFT equation of state. However, the average molecular weight of the asphaltenes had to be assumed to be 1700-4000, depending on the system.