For centuries, scientists and engineers dreamed of being able to peer into the interiors of microscopic and macroscopic objects. A variety of imaging techniques, both invasive and non-invasive, have been developed to accomplish this goal. The present article provides an overview of our work on non-invasive imaging techniques being used and developed for basic and applied sciences. The details of various developments in setting up X-ray and neutron imaging techniques for applications in the Indian nuclear programme, development of two- and three-dimensional tomography for industrial applications, digital medical imaging, X-ray diffraction imaging for exploring the condensed matter at normal and high pressure conditions, X-ray holography for atomic resolution imaging, phase-sensitive imaging and imaging of transient phenomenon are discussed in this paper.