The energy spectrum of electrons produced in the multiphoton ionization of rare gases in the 1012-1015 W.cm-2 range displays interesting features. Firstly, the energy spectrum does not correspond to a single electron peak as would be expected in an N-photon ionization described by the lowest order perturbation theory. It generally consists of a series of peaks evenly spaced by an amount equal to the photon energy. The number of peaks strongly depends on the laser wavelength. For example with Xe, only one additional peak is observed at short wavelengths, while about ten and even tens of peaks are observed at longer wavelengths such as 1064 nm. These absorption processes can be described in terms of continuum-continuum transitions, or better still, in terms of the absorption of photons by an electron in the field of the ion to which it was originally bound. Furthermore, as soon as the electron-ion pair is formed, the electron acquires a quiver energy A in the presence of the e.m. field. The absorption of additional photons, corresponding to an energy less than A, is made energetically impossible. This leads to the suppression of the first peaks of the electron energy distribution. The disappearance of a certain number of electron peaks strongly depends on laser wavelength and laser intensity. The disappearance of nearly 30 peaks has been observed for He at 1064 nm and 1015 w.cm-2. Finally, additional effects, such as electron angular distributions and space charge effects can change the relative amplitude of the first electron peaks. These effects must be taken into account before any comparisons can be made between theory and experiment.