Preface.- What’s “cool” on eriophyoid mites?.- Behavioural studies on eriophyoid mites: an overview.- Plant–eriophyoid mite interactions: cellular biochemistry and metabolic responses induced in mite-injured plants. Part I.- Plant–eriophyoid mite interactions: specific and unspecific morphological alterations. Part II.- Host-plant specificity and specialization in eriophyoid mites and their importance for the use of eriophyoid mites as biocontrol agents of weeds.- Effectiveness of eriophyid mites for biological control of weedy plants and challenges for future research.- The impact of eriophyoids on crops: recent issues on Aculus schlechtendali, Calepitrimerus vitis and Aculops lycopersici.- An insight into some relevant aspects concerning eriophyoid mites inhabiting forests, ornamental trees and shrubs.- The role of eriophyoids in fungal pathogen epidemiology, mere association or true interaction?.- The control of eriophyoid mites: state of the art and future challenges.- Adventive eriophyoid mites: a global review of their impact, pathways, prevention and challenges.- DNA-based methods for eriophyoid mite studies: review, critical aspects, prospects and challenges.- Collection and detection of eriophyoid mites.- Recommended procedures and techniques for morphological studies of Eriophyoidea (Acari: Prostigmata).