Book excerpt: Fourteen informative papers dealing with their DNA, species interactions, adventiveness, host specificity, potential as boi-contol agents of weeds, chemical control, behaviour, their role in fungal pathogen epidemiology, influence in forests and on ornamentals, collecting and mounting techniques and their interaction with crops are presented here. This is an extensive and valuable contribution to eriophyoid science and a must for present and future researchers in this field.