Lockerby's test (2005, Phys. Fluid) the most common high-order continuum equation sets(Grad's 13 th moment, Burnett, and super-Burnett equations)cannot capture the Knudsen Layer, Variants of these equation families have however, been proposed and some of them can qualitatively describe the Knudsen layer structure. the quantitative agreement with kinetic theory and dSmc data is only slight result from kinetic theory. We find that, for a benchmark case, the most common higher-order continuum equation sets(Grads 13 moment, Burnett, and super-Burnett equations) cannot capture the Knudsen layer. Variants of these equation families have, however, been proposed and some of sm (Pe sul a suin IMt et Nar stles lan ll wats them can qualitatively describe the Knudsen layer structure. To make quantitative comparisons, we f-h artaud lume t- b NGk Biwa i-l Ikale ef the ILN obtain additional boundary conditions(needed for unique solutions to the higher-order equations) from kinetic theory. However, we find the quantitative agreement with kinetic theory and DSMc ata is only slight. o 2005 American Institute of Physics. [ DOI: 10.1063/1.]Lockerby’s test (2005, Phys. Fluid)  = const the most common high-order continuum equation sets (Grad’s 13 moment, Burnett, and super-Burnett equations ) cannot capture the Knudsen Layer, Variants of these equation families have, however, been proposed and some of them can qualitatively describe the Knudsen layer structure … the quantitative agreement with kinetic theory and DSMC data is only slight