  We present a protocol to deterministically prepare the electromagnetic field
in a large photon number state. The field starts in a coherent state and,
through resonant interaction with one or few two-level systems, it evolves into
a coherently displaced Fock state, without any post-selection. We show the
feasibility of the scheme under realistic parameters. The presented method
opens a door to reach Fock states with $n\sim100$ and optimal fidelities above
$70$%, blurring the line between macroscopic and quantum states of the field.
