  A general consensus now is that there are two physically inequivalent
complete decompositions of the nucleon spin, i.e. the decomposition of the
canonical type and that of mechanical type. The well-known Jaffe-Manohar
decomposition is of the former type. Unfortunately, there is a wide-spread
misbelief that this decomposition matches the partonic picture, which states
that motion of quarks in the nucleon is approximately free. In the present
monograph, we reveal that this understanding is not necessarily correct and
that the Jaffe-Manohar decomposition is not such a decomposition, which
natively reflects the intrinsic (or static) orbital angular momentum structure
of the nucleon.
