The book gives an account of the major crop plants, their origin and diversification. It also deals with collection, conservation and management of crop plant genetic diversity for future use. It emphasises the dependence of adaptive change on the availability of genetic diversity, expressly for human survival in a changing world and suggests urgent research in the area of crop-diversity conservation. It concludes by placing genetic diversity in the wider context of the conservation of the biosphere.

The crops used by human beings are based on millennia of selection and refinement of a few species, which are the presently available basis for human survival (more species under the lesser known "hidden category" are emerging now).

The authors have set the tone in the very first chapter by recognizing 3 general principles for a coordinated strategy for conserving crop plant genetic diversity: 1) the need for planning and for operational decisions to be based on prior analysis of existing data, rather than on inspired intuition; 2) the need for the focus of activity to be the crop species or species groups rather than the country or region; 3) the essential need for active international collaboration.

In subsequent chapters, they try to elaborate. The 2 chapters on the collection and conservation strategies of genetic biodiversity, and the criteria that should determine the strategies, are of particular interest to all non-governmental voluntary organisations working in the field, and also to planners and administrators concerned with conservation efforts.

While a set of guiding principles at a global level is crucial to collaborative action for conservation by the world community as a whole, the implementation of the 3 principle tasks are easier said than done. They are a) defining objectively the problems to be addressed in conserving the biosphere, without regard for the vested interests of particular organisations or countries; b) production strategies for addressing the problems it had defined, based on up-to-date science as well as political and economic realities, placing existing conservation efforts within this strategic framework and commissioning new projects to fill gaps in accordance with agreed priorities; c) mobilising and channelling resources, financial and human, on a scale commensurate with the defined needs.

A collaborative effort such as this has to be based on reconciling global concerns with national/regional perceptions based on local values and socio-economic realities. The authors have hit upon the crucial point of concern when they suggest that the 2 major issues which appear at the moment to be fundamentally opposed to each other are the desperate need to increase food production in the poorest countries and the equally urgent requirement to modify modern food production systems so that they become "sustainable".

Put in this context, the attempt to have a sustainable agriculture that is based on maximimising yield from low-input syustems, will have to turn back to the genetic diversity available in the land races and primitive varieties. This contrasts with the general agricultural trend so far -- to narrow the crop base of the world's agriculture.

In the preface, the authors suggest that the book is intended for a range from scientists of other disciplines to students, politicians to policymakers -- above all, to taxpayers who are interested in conservation issues and who ultimately determine what resources are devoted to the protection of the environment and the genetic diversity of our crops.