An informative and useful account of complex numbers that includes historical anecdotes, ideas for further research, outlines of theory and a detailed analysis of the ever-elusory Riemann hypothesis. This book bridges any gaps that might exist between the two worlds of lattice sums and number theory. It is designed to provide the reader with an introduction to the theory of complex numbers, ranging from elementary concepts to more advanced circumstances such as contour integration. The book provides details of important scientific investigations and mathematical research. "Complex Numbers" offers a fresh and critical approach to the research based implication of an intriguing mathematical concept.