Errata Rule: Primary Sources
When you find a disagreement between two D&D® rules
sources, unless an official errata file says otherwise, the
primary source is correct. One example of a
primary/secondary source is text taking precedence over
a table entry. An individual spell description takes
precedence when the short description in the beginning
of the spells chapter disagrees.
Another example of primary vs. secondary sources
involves book and topic precedence. The Player's
Handbook, for example, gives all the rules for playing
the game, for playing PC races, and for using base class
descriptions. If you find something on one of those
topics from the DUNGEON MASTER's Guide or the
Monster Manual that disagrees with the Player's
Handbook, you should assume the Player's Handbook is
the primary source. The DUNGEON MASTER's Guide is the
primary source for topics such as magic item
descriptions, special material construction rules, and so
on. The Monster Manual is the primary source for
monster descriptions, templates, and supernatural,
extraordinary, and spell-like abilities.