Kenneth Mathers and J. L. Jinks, authors of *Biometrical Genetics*, respond to Professor Falconer's review of their book. They address two main points raised by Professor Falconer. First, they clarify that their approach is not limited to the study of randomly breeding populations but includes a significant chapter dedicated to analyzing such populations, both naturally occurring and experimentally bred. They emphasize that their methods, while less detailed than those for true-breeding lines, are robust and applicable to a wide range of populations, including human and animal populations. Second, they acknowledge Professor Falconer's disappointment about the lack of discussion on the application of their methodology in plant breeding and genetical architecture. They explain that they have written extensively on these topics elsewhere and that including more material would have made the book too long. The authors reiterate their gratitude to Professor Falconer for his valuable feedback.Kenneth Mathers and J. L. Jinks, authors of *Biometrical Genetics*, respond to Professor Falconer's review of their book. They address two main points raised by Professor Falconer. First, they clarify that their approach is not limited to the study of randomly breeding populations but includes a significant chapter dedicated to analyzing such populations, both naturally occurring and experimentally bred. They emphasize that their methods, while less detailed than those for true-breeding lines, are robust and applicable to a wide range of populations, including human and animal populations. Second, they acknowledge Professor Falconer's disappointment about the lack of discussion on the application of their methodology in plant breeding and genetical architecture. They explain that they have written extensively on these topics elsewhere and that including more material would have made the book too long. The authors reiterate their gratitude to Professor Falconer for his valuable feedback.