The amyloid beta peptide as the major culprit of Alzheimer's disease pathogenesis entered the research arena about a decade ago. The amyloid cascade hypothesis was vividly discussed, supported and contested. Has it held up to all challenges until today? It is alive as ever. The recent identification of the key enzyme involved in amyloid beta generation offered a new target for drug discovery and a novel therapy approach using immunization has successfully eliminated plaque burden in a transgenic mouse. Neurofibrillary tangles, the other hallmark of the disease, were induced in an animal model by amyloid beta peptide.