The theories of electronic structures in amorphous semiconductorsrnare reviewed. The effectiveness of the study ofrnelectrical conductions particularly the SCLC, TSC and transientrnphotoconductivity, in providing a wealth of information onrnelectronic properties of disordered solids also discussed.rnAnalytic equations describing the above three conductionrnproperties are also developed. Experimental study of the SCLC,rnTSC and transient photoconductivity is made fora_TNF and a-Se.rnDistinctly from the models that are based on the assum~rntions of discrete or uniform distributions of traps in energy,rnour experimental works on a~TNF and a-Se indicate the existencernof energetically dispersed charge carriers trapping states.rnThe observed space charge limited mode of conduction and itsrntemperature sensitivity is found to be best describable intermsrnof a smoothly varying distributions. The Gaussian distributionrnseems more realistic for the interpretation of experimentalrnresults in a~TNF and a~e.rnBoth hopping and multiple trapping models are used inrninterpreting the transient photo-conductivity experimentalrnresults for a-TNF and a.,.Se respectively. Drift mobilities ofrncharge carriers are seen to exhibit an activated nature andrnalso found to be field dependent in a manner similar to thernpoole~Frenkel mechanism. For an explanation of the dispersivernhole transport in a-Se interms of the multiple trapping model,rnthe theoretical predictions developed on the basis of arnGaussian distribution is found to agree with experimentalrnresults more satisfactorily.rnThe study of thermally stimulated current characteristicsrnin a-TNF near the glass transition temperature, Tg, renders anrnactivation energy which is significantly different from resultsrnof low temperature TSC analysis. Rather, it is nearly identicalrnto the zero field extrapolated activation energy computedrnfrom transient photo conductivity experiments. There byrnindicates this energy parameters to contain the disorderrninduced term