Some physical applications of atomic absorption spectroscopy for determining the damping parameter a, oscillator strength values f and temperature T have been critically discussed. Potentialities and limitations of the “curve-of-growth” method for determining the a-parameter and collisional width Δ v L of resonance lines are investigated. The new high-precision method for determining the a-parameter based on measuring the total (with continuum source) and line (with sharp-line source) absorption is described. The simplified method for taking into account the effect of hyperline structure on line absorption is proposed. Systematic measurements of Δ v L -values for the resonance lines of I–III groups of elements allowed to find out some regularities in the variation of Δ v L within the groups. The experimental data are in good agreement with the theory. The greatest limitation of the atomic absorption method for determining the absolute f-values is the estimation of the effective length of the absorbing vapor cloud. The features of different atomization techniques (nebulizer-flame, furnace-in-flame, graphite cuvette) are considered from this point of view and the important advantages of the high temperature reducing flames are revealed. The theoretical considerations are confirmed by the results of determining the absolute f-values for the resonance lines of the alkaline-earth elements. The potentialities of the line absorption method for simple, quick and precise determination of the relative f-values are pointed out. The range for the application of simplified calculation methods are outlined. Some limitations of the use of the classical emission methods for determining the temperature of nonuniform media are noted. The new method for determining the effective temperature based on absorbance measurements for the two lines of one element with different low energy levels is described. This method was used for solving some problems of atomic absorption analysis.