This lecture covers the principles of lensless imaging, including the comparison between lens and lensless systems, the concept of phase-retrieval, and the use of coherent x-ray diffractive imaging. It also discusses the application of lensless imaging in small-angle x-ray scattering (SAXS) for studying noncrystalline and crystalline samples, as well as the challenges and advantages of using direct laser writing spatial resolution (DLSRs) in this context.