This paper poses a series of fundamental educational challenges about menta
l health. First, it questions whether 'mental health' is a valid concept, i
n the light of debates over mind/body dualism. If the concept is valid, sho
uld the absence of mental health be seen as an illness, an adaptive strateg
y or simply a statistical eccentricity? Fulford's concept of 'failure of in
tentional action' is commended as a philosophical basis for unravelling the
se issues. Secondly, the paper considers whether diagnosis is a simple or c
omplex process, and whether it can be an objective activity or one which in
volves a strong subjective element. The current and potential value of mult
iaxial classification systems are discussed. Thirdly, themes concerning men
tal health treatment are introduced, covering problems with consent and pat
ient preference, the evidential basis of interventions, and the range and l
imitations of possible treatments. Finally, the paper reviews the education
al processes needed to meet these challenges effectively. It recommends the
develop- ment of multifaceted educational programmes, nurturing a spirit o
f critical enquiry and personal awareness and, above all, the recognition a
nd toleration of the uncertainty and complexity which lie at the heart of s
uccessful medical practice.