  We present detailed spectral and temporal characteristics both in the hard
X-ray (>10 keV) and soft X-ray (<10 keV) domains, obtained using data from
INTEGRAL, XMM-Newton, ASCA and RXTE. The INTEGRAL time-averaged total spectrum
shows a power-law like shape with photon index Gamma = 0.93 +/- 0.06. 4U
0142+61 is detected up to 229 keV and the flux between 20 keV and 229 keV is
(15.01 +/- 0.82) x 10^(-11) erg/cm^2/s. Using simultaneously collected data
with the spectrometer SPI of INTEGRAL the combined total spectrum yields the
first evidence for a spectral break with a peak energy of 228 +65/-41 keV.
There is no evidence for significant long-term time variability of the total
emission. Pulsed emission is measured with ISGRI up to 160 keV. The 20-160 keV
profile shows a broad double-peaked pulse with a 6.2 sigma detection
significance. The total pulsed spectrum can be described with a very hard
power-law shape with a photon index \Gamma = 0.40 +/- 0.15. We performed
phase-resolved spectroscopy over the total high-energy band (2.8-300 keV) and
identify at least three genuinely different pulse components with different
spectra. The high level of consistency between the detailed results from the
four missions is indicative for a remarkable stable geometry underlying the
emission scenario.
