"The text under review collects under a single cover a number of important theoretical results on delay differential equations, both ordinary and partial; these results can be applied for the analysis of relevant mathematical models of population dynamics. This text is a valuable resource for researchers and graduate students in mathematics who study stability properties and oscillation of solutions for various classes of delay differential equations; it contains many useful mathematical results and a rich list of references." (Svitlana P. Rogovchenko, Mathematical Reviews, February, 2016) "This book concerns the behaviour of a particular class of delay differential equations . The book should be of interest to those interested in proving results about the behaviour of delay differential equations." (Carlo Laing, zbMATH 1312.37001, 2015).