This publication reviews the cooling tower water treatment technologies, and recommends the future research directions. The subjects covered in this publication include: (a) cooling tower categories; (b) cooling tower types based on air flow directions; (c) cooling tower types based on air drafts; (d) tower and boiler operations, evaporation, blowdown, drift, leaks, make-up water, and cycles of concentration; (e) cooling tower problems and management, scale fouling, biofouling, fouling control, corrosion control, blowndown treatment, side-stream treatment, cooling tower O&M; (f) maximum water quality parameters and concentrations ; (g) chiller electric power use; (h) chiller tonnage and cooling tower tonnage; (i) daily water use for a cooling tower; (j) boiler and steam systems operation and management; (k) best management practices; (l) cooling systems and boiler systems operation and maintenance tips; (m) chemical treatment processes, chlorination, hypochlorination, chlorine dioxide, bromination, ozonation, ion exchange, corrosion inhibitor, scale inhibitor, biofilm inhibitor; (n) non-chemical physical water treatment, fixed field magnetic system, pulsed power and electrodynamic field system, cavitation system, electrolysis system, ultrasonic system, UV, filtration, membrane filtration, advanced oxidation process, and industrial vortex generator for cooling tower technology; (o) combined physicochemical water treatment ; (p) best management practices (BMP), and (q) innovative processes for future research. This publication has been written as a memoir in memory of the authors’ lifetime colleague, Lubomyr Kurylko, and the authors’ favorite student, Aimee E. Thayer at the Lenox Institute of Water Technology .