The definition of problem-based learning (PBL) as an educational concept is as elusive in 2008 as it has been since the concept was first expressed over forty years ago. A definitive guide to the practice of PBL is equally elusive. Like all worthwhile educational ideas, JIB], has proved attractive to those teachers who seek improvements for their courses. Its appeal has transcended the traditional boundaries in formal education so that there are examples of PBL from primary to tertiary education, and across many disciplines within these. Dissemination, however, has wrought confusion in Understanding and practice, and consequent difficulties For researchers in evaluating its efficacy, and lack of clear advice for those Who would like to adopt PBL. Rather than attempting to he definitive, this Guide explores the various interpretations and practices that claim the label PBL, and critiques these against the original concept and practice. The primary aim is to provide insight into the causes of the confusion about PBL in 2008. The second aim is to point,I feasible way forward so that, where appropriate, the potential of PBL as a whole-of-curriculum concept may be realised, and, where it is not possible to implement the whole concept, worthwhile educational principles that have been associated more or less with PBL may he recognised as Such and given value in their own right.