Why the PSD is a System and Not a Collection Of Books

The PSD was not conceived as a set of independent books.
It was designed as a progressive training system, where each level prepares the next.

A book collection allows reading.
A system enables formation.

The PSD System integrates:

Conceptual foundations

Intellectual formation

Operational specialty

Guided training

Separating these elements results in partial knowledge, but not sustainable professional judgment.