This publication on log houses aims primarily to look upon log-houses from a detailed functional perspective. The focus is mainly on two important ingredients. One is that experienced craftspeople should be involved in surveys, analyses and interpretations of older craft-produced buildings. The other important ingredient has been to work closely with architects who have extensive experience in detailed documentation and presentation. Therefore this study consists of more than three hundred drawings and sketches. The publication have a thematic structure in which log houses are described in terms of their materials and wood processing, timber frames, flooring, fireplaces with chimneys, ceilings, and log joints. In detail, there are great differences between various log building traditions and log joints. Therefore the last chapter about log joinery largely deals with regional characteristics. Five craftspeople from different regions have chosen the log technique that is most common in the area in which they work.