This book is fundamental for plant biotechnologists at this moment, due to the extensive use of in vitro culture. Although some books about somaclonal variation were published some years ago, the circumstances in this field have undergone a great change in the last years. Much progress has been achieved in plant in vitro culture: new technologies have been developed, previously used protocols have been modified with regard to optimization, and in vitro techniques have been applied to new species. Besides, tools for somaclonal variation analysis have also changed in the last years. The techniques and instruments have substantially improved, with the development of new molecular markers and the increased precision and sensitivity of some instruments. Furthermore, novel knowledge about the basic mechanisms underlying somaclonal variation has been obtained recently, which can be very useful for explaining the variability found in different experimental systems.