A portable anomaly detection apparatus for inspecting an electrically conductive object, the apparatus comprising: an electromagnetic field emitter (52, 60) operable to produce a time varying magnetic flux field for passing through at least a portion of the electrically conductive object, and thereby to generate an electrical eddy current field in the electrically conductive object; said electromagnetic field emitter (52, 60) having a flux focussing core, said flux focussing core including a pole piece, a back plate portion and a peripheral wall, said peripheral wall being spaced away from said pole piece, said peripheral wall forming a closed periphery, said pole piece, said back plate portion and said peripheral wall being made of highly magnetically permeable material and forming a continuous high permeability path; said pole piece having a centerline axis; there being a gap defined between said pole piece and said peripheral wall, said gap between said pole piece and said peripheral wall being annular; there being an exciter coil wound about a portion of the pole piece; said apparatus having a sensing end for placement next to the electrically conductive object to be inspected; eddy current monitoring circuitry (70, 94) including an array of eddy field divergence sensor coils arranged in a pattern about said centerline axis and comprising at least two sensing coils, said array being adj acent to respective distal ends of said pole piece and peripheral wall; a first and a second of said sensing coils being eccentric relative to said centerline axis of said pole piece, and being positioned to monitor a first and second sector of the annular space of said gap between the pole piece and the peripheral wall at said sensing end, the second sensing coil having a different footprint than said first sensing coil; and signal processing apparatus connected to said eddy current monitoring circuitry (70, 94); and at least one of (a) a recorder operable to store data observed with respect to said first and second sectors; and (b) the signal processing apparatus being operable to compare at least one of (i) data observed with respect to said first sector and data observed with respect to said second sector; and (ii) data observed with respect to at least one of said first and second sectors and a reference datum; and wherein said first sector includes at least a portion not covered by said second sector, and said second sector includes at least another portion not covered by said first sector; and said first and second sectors are non-concentric. an electromagnetic field emitter (52, 60) operable to produce a time varying magnetic flux field for passing through at least a portion of the electrically conductive object, and thereby to generate an electrical eddy current field in the electrically conductive object; said electromagnetic field emitter (52, 60) having a flux focussing core, said flux focussing core including a pole piece, a back plate portion and a peripheral wall, said peripheral wall being spaced away from said pole piece, said peripheral wall forming a closed periphery, said pole piece, said back plate portion and said peripheral wall being made of highly magnetically permeable material and forming a continuous high permeability path; said pole piece having a centerline axis; there being a gap defined between said pole piece and said peripheral wall, said gap between said pole piece and said peripheral wall being annular; there being an exciter coil wound about a portion of the pole piece; said apparatus having a sensing end for placement next to the electrically conductive object to be inspected; eddy current monitoring circuitry (70, 94) including an array of eddy field divergence sensor coils arranged in a pattern about said centerline axis and comprising at least two sensing coils, said array being adj acent to respective distal ends of said pole piece and peripheral wall; a first and a second of said sensing coils being eccentric relative to said centerline axis of said pole piece, and being positioned to monitor a first and second sector of the annular space of said gap between the pole piece and the peripheral wall at said sensing end, the second sensing coil having a different footprint than said first sensing coil; and signal processing apparatus connected to said eddy current monitoring circuitry (70, 94); and at least one of (a) a recorder operable to store data observed with respect to said first and second sectors; and (b) the signal processing apparatus being operable to compare at least one of (i) data observed with respect to said first sector and data observed with respect to said second sector; and (ii) data observed with respect to at least one of said first and second sectors and a reference datum; and (a) a recorder operable to store data observed with respect to said first and second sectors; and (b) the signal processing apparatus being operable to compare at least one of (i) data observed with respect to said first sector and data observed with respect to said second sector; and (ii) data observed with respect to at least one of said first and second sectors and a reference datum; and (i) data observed with respect to said first sector and data observed with respect to said second sector; and (ii) data observed with respect to at least one of said first and second sectors and a reference datum; and wherein said first sector includes at least a portion not covered by said second sector, and said second sector includes at least another portion not covered by said first sector; and said first and second sectors are non-concentric.