This book is intended as a main text in the basic theory and principles of soil mechanics, to serve the needs of undergraduates and technicians and practising engineers in the fields of building and civil engineering. It is assumed that the reader will have a basic grounding of mathematics and science, particularly basic mechanics. The text of the book is designed to be used primarily in the context of learning, by students under tuition. Fundamentals and principles are clearly set out in a manner which is intended to be concise and yet still provide a sufficiently comprehensive treatment. The author expects students to have, and indeed relies on them having, the expert help and advice of good teachers. The need for a good foundation of knowledge is undeniable; a firm grasp of basic principles is required for this purpose. In the author's experience of teaching, however, it has become apparent that the best learning situation develops from an application of principles. The book consequently contains a large number of worked examples within the text and a quantity of practice exercises at the end of chapters. It is essential for students to come to grips with simple practical problems as soon as problem prior to an exposition of the theory. Although, as the title states, this is a book of basic soil mechanics, it is probable that many readers will want to retain their copy for use in more advanced studies and later in engineering practice. Some topics have, therefore, been taken beyond the fundamental stage and examples of a more advanced level provided for the more experienced reader. A list of quoted references is given at the end of the book, which students will find useful as a source for further reading. The topic coverage should therefore be sufficiently comprehensive so as to meet the needs of students at all stages in their courses of study, as well as those of post-graduate workers and professional engineers.