“The authors succeed admirably in their aim of demonstrating that the theory of numbers has applications. … The account is accessible, well-paced and unified and leads the reader along from the introductory ideas to recent advances. Each chapter has exercises inviting the reader to compute and fill in details in the proofs.” (John H. Loxton, Mathematical Reviews, April, 2016)“The book is intended to be usable as a text … . It would also be useful for those of us who received our training in number theory in the days before it had any applications and wanted to find out about them. … The writing is clear and lively. … The book is pleasant to the eyes, and in the hands. … It is an estimable book that I hope is successful.” (Underwood Dudley, MAA Reviews, maa.org, January, 2016)