This book presents the work done by the RILEM Technical Committee 274-TCE. It focuses on the estimation of the parameters which are necessary to properly design earthen constructions. It provides a compilation of the value classically obtained for the key parameters of earthen materials, a pedagogical presentation of the main testing procedures for earthen materials, their advantage and their drawback and an overview of most standards on earthen materials, whatever their origin and their language. The book is divided into eight chapters. After a general introduction on earthen materials and constructions, the state of the art on the material characterisation technics, the assessment of hygrothermal performance, the mechanical behaviour, seismic resistance and the durability will be presented, each in a dedicated chapter. On the basis of these last chapters, a critical review of the standards which are used for earthen material will be presented in the last chapter. The last chapter is dedicated to the analysis of the environmental potential of earth-based building materials.