ear Colleagues,The proportion of elderly people in the general population is increasing yearly, posing a numberof specific, and of course other less specific, problems.Some diseases develop in older patients in a form continuous with that seen in younger adults,while others are more characteristic of an older age group. One such example is cognitive pathologies:- Some are specific deficits which either turn out to be early manifestations of a generalizeddeterioration in the cognitive state, or remain specific, their progression being limited to thefunction initially affected.- Others affect various aspects of cognition, and the outcome can either be an exacerbationof the initial problems observed, or an extension of these, either with or without exacerbation.- Unfortunately, a large number of different pathologies will develop into a generalized dete-rioration of the cognitive state, with behavioral and neurologic disorders, meeting all thecriteria for Alzheimers disease.The amplitude of these diseases, both qualitative and quantitative, has created significant concerns,both for large numbers of the population as they experience the aging process, and for researchers,both within and outside the industry, regarding methods of prevention, diagnosis, and treatment.This of course brings us to genetics, and to individual biological makeup and environmentalfactors:- Is there a genetic predisposition to neurodegenerative diseases?- Are some individuals made more vulnerable due to the genetics of individual biological con-stitution?- Is there a social or environmental predisposition which leads certain individuals to experi-ence this cognitive deterioration?Naturally, this raises the issues of early detection of these problems, their epidemiology, ofpreventive and curative measuresparticularly pharmacological, as well as associated pathologies.As you will see, these various questions have been addressed in this issue of Dialogues in ClinicalNeuroscience, by a distinguished group of authors who are specialists in their areas. I would like to thankthem all, and I would also particularly like to thank my two colleagues who have applied their knowledgeand talent to the coordination and creation of this issue: Professors Michael Davidson and Barry Lebowitz.Best regards,Jean-Paul Macher, MDE d i t o r i a lD