This talk will review design and implementation of rectenna arrays for wireless power transfer and harvesting. For low power levels, each antenna element contains a rectifier and the rectified dc power is summed. At ultra-low incident power densities in the case of harvesting, a sub-array might be necessary to turn on a rectifying element and strategies for arraying will be discussed. For beaming applications, power handling limitations demand either more distribution or higher-power rectifier topologies. Finally, efficient transmitters are an integral part of a far-field WPT system and will be briefly summarized.