Nucleon Spin Structure and Gauge Invariance (An Atomic View)

The theory and measurements of the quark and gluon contributions to the spin of the nucleon have caused controversy and consternation. I review some of the issues in the familiar context of atomic physics and present the Nanjing collaboration view of how to resolve these questions. The principle featue of our resolution is a separation of the contribution of gauge fields to the relevant operators into two distinct, indentifiable components.