more spatially extended than stellar halos only in gas-rich galaxies that also have a high global specific frequency.

    The implication that $\epsilon_{\rm cl}$ might have had a universal value is supported by global GCS data for a sample of 97 giant ellipticals, brightest cluster galaxies, and faint dwarfs. The total globular cluster populations in all of these early-type systems are in excellent agreement with the predictions of a constant $\epsilon_{\rm cl}$ at the level observed directly in M87, M49, and NGC 1399; all [*systematic*]{} variations in GCS specific frequency between galaxies are shown to result entirely from different relations, in different magnitude ranges, between $M_{\rm gas}^{\rm
    init}$ and the present-day $L_{V,{\rm gal}}$. An identical $\epsilon_{\rm cl}$ is also calculated for the Pop. II spheroid of the Milky Way, and is indicated (although less conclusively) for the ongoing formation of open clusters. The inferred universal cluster formation efficiency, of $\simeq$0.25% by mass, should serve as a strong constraint on general theories of star and cluster formation. The associated inference of a non-universal formation efficiency for unclustered stars is considered, particularly in terms of the suggestion that this might result, both in dwarf galaxies and at large galactocentric radii in the brightest 