This chapter discusses fundamentals of magnetic resonance image production. Linear magnetic field gradients are described. The traditional ‘high resolution’ magnetic resonance signal, observed by placing a (bio) chemical specimen in a highly homogeneous B0 magnetic field, may be said to have zero spatial dimensionality. Physical gradients of the MRI scanner are described. Overall ability to generate an image in a plane with arbitrary orientation is a major advantage of the MR imaging modality. In any case, for diagnostic examinations, the slice selection direction is always perpendicular to the viewing surface. Frequency encoding is explained. Two types of rephased echoes are in use in MR imaging, that are the spin-echo (SE), and the ‘gradient-recalled’ echo or simply, the gradient-echo (GE). When longitudinal recovery of the spin moments towards equilibrium is occurring in one excited slice, a spin-echo can be acquired from another slice. Conventional SE imaging is associated with long image acquisition times. Use of the parameters TR and TE in producing image contrast are explained. The parameters can be varied to achieve contrast sensitivity in MR images. The MR image intensity represents the tissue characteristics of a specific slice through the patient’s body. Image reconstruction and the ‘display’ matrix are described. The image data matrix is obtained via the 2D Fourier transformation of the raw data matrix, and this is performed by the array processor of the MRI scanner. Linear magnetic field gradient pulses, when imposed on the main magnetic field in a controlled manner, achieve selective activation of tomographic tissue slices, and the encoding of spin-echo or gradient echo MR signals from an activated slice into spatially resolved frequency and phase dimensions.