Is there a composition gradient in the halo?

We define “metals” as consisting of the elements at and near the Fe-peak, and review several methods by which the metal-abundance gradient of stars in the halo can be obtained. In the inner halo (galactocentric distance R ≲ 8 kpc), the Basel RGU photometry should allow the derivation of the shapes and dimensions of the iso-abundance contours. For the outer halo to R ∼ 30 kpc, we review techniques based on Δs-measurements of RR Lyraes (Lick) and intermediate band-pass photometry of globular-cluster giants (Searle and Zinn, Palomar). Both methods suggest little change in mean [Fe/H] between 10 and 30 kpc; however, both may be biased against the discovery of very metal-poor objects. The conclusion that the outer halo has no abundance gradient may be somewhat premature.