This book concerns with the problems of determining Gaussian integer solutions to quadratic equations with three & four variables and a notable collections of problems are presented. In each illustration, different sets of Gaussian integer solutions are exhibited. Of course, to have a deep and thorough knowledge of the illustrations presented in this book, a lot more than reading these problems must be done with sincere devotion. The authors wish that there problems may inspire the researchers to innovate more problems on multi degree multivariate Diophantine equations for obtaining non-zero distinct Gaussian integer solutions. It is worth to note that the voyage of discovery and the true pleasure lies in the search for new problems and it happens only when we step outside our comfort zone.