This is a book on Development and Performance Evaluation of Medical Image Fusion using Undecimated DWT, Fuzzy Sets and Optimization Techniques. This Book makes Engineers, Radiologists and Doctors in better diagnosing a disease. Medical image fusion is an important tool in image processing. Medical images provide different types of information. It has turned into a typical practice in medical diagnostics and treatment to assist and extract image structures that may not be normally noticeable in images created by single modalities. CT image provides details of dense structures whereas MRI gives soft tissue information. Fusing both the images additional information is extracted in a single image called fused image. Various multimodal medical image pairs such as CT-MRI, MRI-PET, MRI-MRA, Xray-VA, MRI-SPECT and PET-CT are used in this work to extract additional clinical information.