Accessory dwelling units (ADUs) are good for people and communities. An inside look at 25 charming, ultra-functional, extra living spaces will inspire you to build one of your own! An Accessory Dwelling Unit (ADU) is a smaller housing unit built on the same lot as a primary dwelling (also known as Additional or Auxiliary Dwelling Units) — think granny flat, in-law unit, laneway house). It has an arrangement for sleeping, cooking, and lavatory. An ADU can be detached, attached, a garage conversion, or a basement conversion. The uses are myriad—for family members, guest spaces, rental income, or more. These attractive, well-designed ADUs are located from coast to coast across the US and Canada. Each house includes information about the type of construction, the major green features, and how it is used. A variety of styles (e.g., laneway houses, garage conversions, and stand-alone independent structures, and ones connected to the primary house) show versatility and ways to blend new ADUS into the architecture of the primary house and neighborhood. Each featured ADU shows how to make the most of the small space for comfortable living without the burden of a big house to care for.