  The force between two interacting particles as a function of distance is one
of the most fundamental curves in science. In this regard, Atomic Force
Microscopy (AFM) represents the most powerful tool in nanoscience but with
severe limits when it is to probe attractive interactions with high
sensitivity. The Force Feedback Microscope (FFM) described here, removes from
AFM the well known jump to contact problem that precludes the complete
exploration of the interaction curve and the study of associated energy
exchanges. The FFM makes it possible to explore tip-surface interactions in the
entire range of distances with a sensitivity better than 1 pN. FFM stands out
as a radical change in AFM control paradigms. With a surprisingly simple
arrangement it is possible to provide the AFM tip with the right counterforce
to keep it fixed at any time. The counterforce is consequently equal to the
tip-sample force. The force, force gradient and damping are simultaneously
measured independently of the tip position. This permits the measurement of
energy transfer in thermodynamic transformations. Here we show some FFM
measurement examples of the complete interaction force curve and in particular
that the FFM can follow the nucleation of a water bridge by measuring the
capillary attractive force at all distances, without jump to contact despite
the large attractive capillary force. Real time combination of the measured
parameters will lead to new imaging modalities with chemical contrast in
different environments.
