Few teachers of the basic medical sciences would dispute the value of a knowledge of embryonic development in the understanding of general anatomy and in the production of congenital defects.

Traditionally, the teaching of the basic aspects of human developmental anatomy is coupled with that of general anatomy and is rendered as part of the preclinical curriculum to students in the medical, dental and allied medical disciplines. Hopefully, when the student studies paedriatrics, some of the basics will have remained to assist in making sense of congenital anomalies. With the worldwide trend to reduce the preclinical sciences to a bare minimum, both anatomy and its essential partners – histology and embryology – will suffer accordingly.

While the authors feel that this trend is unfortunate and undesirable as well as of educational denegation, they feel, nevertheless, that it is necessary to provide students with a text in embryology, with the purpose of indicating, in a simplified way, the essentials of the subject. In this way a reasonable ‘working knowledge' of embryonic development and its aberrations may be acquired.

Not only is this necessary from an educational point of view but also from a practical standpoint in the light of the increasing incidence of congenital abnormalities resulting from the industrial, chemical and radioactive pollution of the earth's surface. The practising doctor is very likely to encounter one or more of these abnormalities in his/her career.

In this text we have attempted to adhere to the ‘fundamental’ aspects of embryonic development, providing a progressive account of the processes which lead to the development of the human organism.

Our goal is to impart to students a comprehensive overview of how the human embryo forms, not only as a basis for the study of human anatomy, but also as a link to possible abnormalities that they will encounter in their clinical careers.

In the near future, genetic engineering will attempt to correct congenital abnormalities. Gene manipulation will challenge normal and abnormal development in an attempt to reduce the risk of, for example, a congenital heart abnormality or a cleft lip. Unfortunately, modern technology may also increase the incidence of certain abnormalities. A thorough grounding in the fundamentals of human development will prepare the professional-in-training for the ‘progress’ of the future. As we progress towards ‘molecular medicine’, we should not lose sight of the basic facts which make humans human.