  This paper reviews quantum oscillation studies of iron-pnictide
superconductors and related materials. These measurements give unique
information regarding the full three dimensional topology of the Fermi surfaces
and the renormalisation of the quasi-particle masses. The review will cover
measurements of the 122 arsenide end members, XFe_2As_2 (X = Ba, Sr, Ca) which
have a spin density wave ground state, but will concentrate on the phosphide
end members (LaFePO and XFe2P2) which have a paramagnetic ground state and a
Fermi surface topology which is similar to the higher Tc superconducting
iron-pnictides. All three of the 122 phosphides become superconducting when P
is partially substituted by As, and for the BaFe2(As1-xPx)2 series de Haas-van
Alphen oscillations are observable for 0:42 \leq x \leq 1 with Tc up to 25 K.
The results show the changes in the Fermi surface topology and the increase in
the mass renormalisation as the correlations which induce superconductivity
develop.
