This book was firstly published in 1957. It deals with triaxial tests and with the ways of meeting the various problems which arise in its use in laboratory. In the first part the basic principles underlying strength and deformation measurement are briefly discussed in relation to the practical problems commonly encountered in soil mechanics. In the second part the principal features of the triaxial apparatus are described. The third part presents the procedure for carrying out standard tests, which should be within the competence of a well-equipped laboratory carrying out either research or commercial testing. Finally, special tests are described in the fourth part, such those that are likely to be encountered in a research laboratory.