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The noble-gas hydrides of general structure HNgY (Ng = Xe, Kr or Ar) were discovered just fifteen years ago [1]. Remarkable progress in this unusual area of low-temperature chemistry was outlined in a recent review [2]. The most common way of preparation of HNgY molecules introduced by the Helsinki team [1] implies direct photoexcitation of suitable HY precursors in solid noble gas matrices followed by controlled annealing, which may induce local or global mobility of H atoms. An alternative approach used in our laboratory [3] exploits high energy radiation (fast electrons or X-rays). In this case, the energy is primarily absorbed by matrix and the precursor molecule is activated due to positive hole or excitation transfer. The dissociation of HY molecules and formation of HNgY compounds were monitored by a combination of EPR and FTIR spectroscopy, including highly informative experiments with monoisotopic xenon matrices [4, 5]. This lecture will summarize the results of our studies during the past decade with special impact on recent findings. The following major aspects will be presented: (i) mechanism of precursor dissociation and involvement of “hot” channels; (ii) production and distribution of hydrogen atoms and relative role of “local” and “global” processes in radiation-chemical and photochemical experiments; (iii) spectroscopic characterization of precursor radicals and HNgY molecules; (iv) “cross synthesis” of HNgY compounds with radiation-chemical generation of precursor radicals; (v) stability of noble-gas hydrides in the presence of other species. Finally, the prospects of synthesis of HNgY molecules in different environment using radiation-chemical approach will be briefly discussed.