The book titled "Rheological Properties of Hydrogels" is structured into five chapters. Rheology of hydrogels refers to the study of their flow and deformation behavior under different conditions. Hydrogels are water-swollen, crosslinked polymer networks, and their rheological properties play a crucial role in determining their performance in various applications, such as drug delivery, tissue engineering, and wound healing.Hydrogels often exhibit non-Newtonian flow behavior, meaning their viscosity depends on the shear rate. At low shear rates, hydrogels behave as viscous materials with high viscosity, while at high shear rates, they display shear-thinning behavior, where viscosity decreases. This characteristic is particularly important for applications like injectable drug delivery, where viscosity influences ease of administration.Additionally, thixotropic hydrogels exhibit time-dependent shear thinning-under stress, they become less viscous, and when the stress is removed, they gradually recover their original structure. This property is especially useful in applications such as controlled drug release or bioinks for 3D printing.