[en] Precise level energies in ³⁸K have been measured up to the region of 6 MeV in excitation with our 100-cm broad-range magnetic spectrograph and the ⁴⁰Ca(d,α) reaction. With a Ge(Li) detector, γ-ray energies were measured in the ⁴⁰Ca(d,αγ) and ³⁶Ar(³He,pγ) reactions. Some 79 states have been identified in this region of excitation, approximately 30 of which have not previously been reported. Uncertainties in excitation energies are 1 to 3.5 keV. Branching ratios for levels up to 5.2 MeV were determined, and particle-γ angular correlations were measured with the ³⁶Ar(³He,pγ) reaction. The mean lives of some levels in ³⁸K excited in the ⁴⁰Ca(d,αγ) reaction at E/subd/ = 7.84 MeV have been determined using the Doppler-shift attenuation method. The following mean lifetimes were deduced (excitation energy in keV, lifetime fs): 3431, < 170; 3615, 700/sub -//sub 3//sub 1//sub 0/⁺⁸⁵⁰; 3688, 95 plus-or-minus 55; 3688, 400/sub -//sub 1//sub 2//sub 0/⁺¹⁶⁰; 3702, > 1100; and 4333, 350/sub -//sub 2//sub 5//sub 0/⁺⁷⁰⁰. The angular correlations, with the lifetimes were deduced (excitation energy in keV, lifetime infs): 3431-, 3615-, and 3688-keV levels, respectively: J/sup pi/ = (2), (3^- or 5^-), (3), where parentheses indicate assignments dependent upon unproven assignments to other levels from the literature. The observed decays further imply J = (1,2) for both the 3857- and 4214-keV levels. Clarifications of several ambiguous and erroneous level identifications in the literature are offered