Frequency-domain model reduction methods for continuous-time, linear, time-invariant, SISO systems are critically reviewed. Particular attention is given to the Maehly's method which often produces satisfactory results but does not entail matching the first terms of the Che byshev expansions of the original and reduced-order functions. The problem is then formulated in a way that allows us to suggest other reduction procedures; to these a method already adopted by the authors with some success may be related. Finally, the relative merits of the considered methods are compared with reference to a numerical example.