With the federal ALP pre-selection season about to kick off, Crikey thought it time to shine a light into the murky tributaries that funnel candidates into the highest elected offices in the land.

Preselection is one of those interminable processes that for the most part flies under the public's radar. Usually, candidates are selected via some division of the grassroots vote and a central Politburo-style committee, but this varies markedly between states.