The scope of this paper is to present the global mechanisms of soil desiccation, including drying shrinkage and cracking. The paper first reviews the basic processes that are beneath the word “desiccation”. Then the results of an experimental study of desiccation are presented, in which strains, suction, water content, degree of saturation and crack geometry are investigated. The results show that cracking initiates close to the onset of de-saturation. Insights into the micro-scale are proposed to explain this observation. A scenario for the processes leading to crack initiation is further established in terms of the macroscopic variables: an assessment of the stress building up is proposed, until a critical point at which the tensile strength is met. Desiccation crack pattern formation is finally discussed.