Complex sentence: Overall, the information provided in the "Novel Series" is generally assumed to be authoritative and superseding the older material; among other sources of authoritative information is the "Horus Heresy" wargame environment, especially the associated "Rulebook Series", and other expansions.
Split into simpler sentences: Overall, the information provided in the "Novel Series" is generally assumed to be authoritative and superseding the older material. Among other authoritative sources are the "Horus Heresy" wargame environment (especially the associated "Rulebook Series"), and other expansions.