Block vs inline macros

Every OurBigBook macro is either block or inline:

a block macro is one that takes up the entire line when rendered
All block macros start with a capital letter, e.g. \H for headers.
and an inline macro is one that goes inside of a line.
Every inline macro starts with a lowercase letter e.g. \a for links.

Some macros have both a block and an inline version, and like any other macro, those are differentiated by capitalization:

Ancestors

Incoming links