The evidence bearing on the derivation of the primordial Li-7 abundance is summarized from observations of extremely metal-deficient stars in the galactic halo (Population II). Arguments, primarily observational, but supported theoretically, are presented to show that the Li-7 observed in warm halo subdwarfs has neither been supplemented by Li-7 production in the early galaxy, nor significantly depleted during the lifetime of the stars themselves, and gives a good approximation to the primordial value. The absence of Be-9 or B-10 + B-11 in these objects at present limits of observational accuracy tends to support the primordiality of their Li-7. Observing Be-9, and heavier nuclides in the most metal deficient stars, does offer a possible route to distinguish between standard and inhomogeneous primordial cosmological models.