Following a short history of its development, the latest advances in the physics of InN and the arguments surrounding the band-gap controversy are critically reviewed. The role of oxygen in the material is examined, with new absorption data presented for the amorphous oxynitride contribution. Assumptions regarding oxygen alloying are dispelled. The recent evidence for a 1.1-1.5 eV band-gap is examined, as well as evidence for the possibility of a ∼0.7 eV trapping centre. Data for the newly discovered nitrogen:InN alloy system, extending out to levels of 33% excess nitrogen, are discussed, as are current techniques for stoichiometry analysis. Finally it is concluded that the current analysis of InN is not yet sufficient to ascribe a known band-gap to the material.