Basics of induction, eddy currents, and core project categories (BFO, VLF, PI). Re-written
The core value of the Overton and Moreland text lies in its demystification of the physics involved. The PDF breaks down the three fundamental pillars of metal detection in a way that is accessible yet rigorous: Basics of induction, eddy currents, and core project
(archive.org) for a scanned copy.