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High-resolution, high-signal-to-noise (<S/N> = 85) spectra have been obtainedfor five stars -- CD-24:17504, CD-38:245, CS 22172-002, CS 22885-096, and CS22949-037 -- having [Fe/H] < -3.5 according to previous lower S/N material. LTEmodel-atmosphere techniques are used to determine [Fe/H] and relativeabundances, or their limits, for some 18 elements, and to constrain moretightly the early enrichment history of the Galaxy than is possible based onprevious analyses.  We compare our results with high-quality higher-abundance literature data forother metal-poor stars and with the canonical Galactic chemical enrichmentresults of Timmes et al. (1995) and obtain the following basic results: (1)Large supersolar values of [C/Fe] and [N/Fe], not predicted by the canonicalmodels, exist at lowest abundance. For C at least, the result is difficult toattribute to internal mixing effects; (2) We confirm that there is {\it noupward trend} in [$\alpha$/Fe] as a function of [Fe/H], in contradistinction tosome reports of the behavior of [O/Fe]; (3) The abundances of aluminum, aftercorrection for non-LTE effects, are in fair accord with theoretical prediction;(4) We confirm earlier results concerning the Fe-peak elements that [Cr/Fe] and[Mn/Fe] decrease at lowest abundance, while [Co/Fe] increases -- behaviors thathad not been predicted. We find, however, that [Ni/Fe] does not vary with[Fe/H], and at [Fe/H] ~ -3.7, [Ni/Fe] = +0.08 +/- 0.06. This result appears tobe inconsistent with the supernova models of Nakamura et al. (1999) that seekto understand the observed behavior of the Fe-peak elements by varying theposition of the model mass cut relative to the Si-burning regions.(abbreviated)Comment: With 12 figures, to appear in The Astrophysical Journa

Extremely Metal‐Poor Stars. VIII. High‐Resolution, High Signal‐to‐Noise Ratio Analysis of Five Stars with [Fe/H] ≲ −3.5