The paper investigates the mass profiles of ΛCDM halos using high-resolution numerical simulations spanning five decades in halo mass, from dwarf galaxies to rich galaxy clusters. The analysis confirms the proposal by Navarro, Frenk, and White (NFW) that the shape of ΛCDM halo mass profiles differs significantly from a power law and is largely independent of mass. The logarithmic slope of the spherically-averaged density profile, measured by \(\beta = -d \ln \rho / d \ln r\), decreases monotonically towards the center and becomes shallower than isothermal (\(\beta < 2\)) inside a characteristic radius, \(r_{-2}\). The NFW fitting formula provides a reasonable approximation to the density and circular velocity profiles of individual halos, with deviations typically less than 10% over the resolved radial range. However, systematic deviations from the best NFW fits are also noticeable, particularly inside \(r_{-2}\), where the profile becomes shallower more gradually than predicted. This discrepancy has been interpreted as indicating a steeply divergent cusp with an asymptotic inner slope, \(\beta_0 \sim 1.5\). The authors propose a simple formula that better reproduces the radial dependence of the slope and may minimize errors when extrapolating results inward to unresolvable radii. They find no evidence for a well-defined central "core" of constant density and conclude that the density profiles do not converge to a well-defined asymptotic inner power law.The paper investigates the mass profiles of ΛCDM halos using high-resolution numerical simulations spanning five decades in halo mass, from dwarf galaxies to rich galaxy clusters. The analysis confirms the proposal by Navarro, Frenk, and White (NFW) that the shape of ΛCDM halo mass profiles differs significantly from a power law and is largely independent of mass. The logarithmic slope of the spherically-averaged density profile, measured by \(\beta = -d \ln \rho / d \ln r\), decreases monotonically towards the center and becomes shallower than isothermal (\(\beta < 2\)) inside a characteristic radius, \(r_{-2}\). The NFW fitting formula provides a reasonable approximation to the density and circular velocity profiles of individual halos, with deviations typically less than 10% over the resolved radial range. However, systematic deviations from the best NFW fits are also noticeable, particularly inside \(r_{-2}\), where the profile becomes shallower more gradually than predicted. This discrepancy has been interpreted as indicating a steeply divergent cusp with an asymptotic inner slope, \(\beta_0 \sim 1.5\). The authors propose a simple formula that better reproduces the radial dependence of the slope and may minimize errors when extrapolating results inward to unresolvable radii. They find no evidence for a well-defined central "core" of constant density and conclude that the density profiles do not converge to a well-defined asymptotic inner power law.