Modern multi-modal imaging has transformed our ability to observe and understand biological processes in living systems. This chapter explores key imaging modalities that have enabled unprecedented visualization of in-vivo processes, including ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET), as well as optical imaging approaches such as fluorescence and bioluminescence. We examine how these tools enable unprecedented visualization of in-vivo processes. We explore the integration of imaging technologies and experimental model systems - from invertebrates to mammals - highlighting their role in bridging laboratory research with clinical applications. Attention is also given to emerging platforms such as organoids and organ-on-chip platforms that offer alternative approaches to traditional animal studies. Versatile understanding of the technical considerations, limitations, and cost-effectiveness of these tools will continue to provide valuable insights into anatomical, functional, and molecular aspects of diverse biological processes.