The recovery of heavy oil and oil sand deposits of western Canada by using in situ combustion or gasification recovery processes has always been a great technological and economical challenge. During in situ combustion bitumen recovery processes, pyrolysis, aquathermolysis and oxidation mechanisms coexist because of co-existence of bitumen, water and oxygen in the presence of high temperature and high pressure. The modeling of such processes requires comprehensive reaction schemes along with kinetic parameters to describe each of these mechanisms. The determination of such kinetic parameters requires extensive lab and/or pilot studies due to the complex chemical nature of bitumen. During these studies, it is customary to represent bitumen and products of bitumen combustion by pseudo-components to describe the bitumen combustion reaction scheme in a way which not only describes the process reasonably well but also is easy to understand. Although there have been numerous bitumen combustion experiments conducted over the past 80 + years, all of the data and experience have not been analyzed comprehensively with a focus towards integrating all of the evidence into a single vision of the process. Here, we review all previously published lab scale and pilot experimental data, various reaction schemes and field observations published for pyrolysis, aquathermolysis, oxidation, and/or gasification of Athabasca bitumen. These studies were conducted either to understand the chemical structure of bitumen or to develop reaction schemes for use in numerical simulators. This review reveals a new overall vision for combustion processes for in situ bitumen recovery and also shows that there are key data sets not currently available that would greatly enhance modeling and simulation work needed for the full recovery of Athabasca bitumen resources. (C) 2014 Elsevier B.V. All rights reserved.