Starting from some fundamentals of solid-state diffusion, we remind the reader to the major techniques for lattice diffusion measurements. Self-diffusion is the most basic diffusion phenomenon in any solid. The paper covers main features of self-diffusion in pure fcc and bcc metals and some important facts about diffusion of substitutional solutes in metals. Binary intermetallics are compounds of two metals or of a metal and a semimetal. Their structures are different from those of the constituents. Some intermetallics are interesting functional materials others have attracted attention as high-temperature structural materials. The paper reviews some results mainly from our laboratory on diffusion in binary intermetallics from the systems Cu-Zn, Ni-Al, Fe-Al, Ni-Ge, Ni-Ga, Fe-Si, Ti-Al, Ni-Mn, Mo-Si and Co-Nb, which have been published in detail elsewhere. Some results for the ternary system Ni-Fe-Al are also mentioned.