  We present a detailed description of the experiment realising for the first
time a protective measurement, a novel measurement protocol which combines weak
interactions with a ``protection mechanism'' preserving the measured state
coherence during the whole measurement process. Furthermore, protective
measurement allows finding the expectation value of an observable, i.e. an
inherently statistical quantity, by measuring a single particle, without the
need of any statistics. This peculiar property, in sharp contrast with the
framework of traditional (projective) quantum measurement, might constitute a
groundbreaking advance for several quantum technology related fields.
