This book discusses the challenges and solutions related to near-field millimeter-wave (MMW) imaging using MIMO arrays. Specifically, the authors focus on the issues of MMW imaging employing arrays in non-planar apertures, which have received limited attention in the existing literature, but are essential for security inspections using MMWs. This book introduces both the MIMO-SAR (using electronic and mechanical scanning) and fully electronic MIMO schemes. It develops and investigates various array topologies as well as fast imaging algorithms in the spatial-frequency domain. Key parameters affecting the imaging performance are systematically analyzed. In addition to the aforementioned topics, this book also discusses the convex optimization-based method for designing sparse MIMO arrays. The authors believe that the comprehensive content of this book can provide valuable insights, knowledge, and inspiration for graduate students, researchers, and engineers working in the field of microwave or millimeter-wave imaging.