The book An Introduction to Drug Carriers provides a broad overview of drug carriers. Drug carriers play medically important roles in delivering drugs to pinpointed regions in biological systems. The cell hosts most of the disorders related to diseases. Therefore, the cell is also considered the main target region for most drugs. Some of the cellular compartments, especially cell-based membranes, which are geometrically constructed with both hydrophobic and hydrophilic layers/boundaries, often appear as barriers against vital candidate drugs' journey to the target regions. Besides, there are off-target structures that need to be avoided for drugs to get adsorbed. Otherwise, drugs may cause unbearable off-target binding originated toxicity, which would reduce the efficacy of the drugs. Appropriate choice of drug carriers may help specific drugs to get conjugated and be delivered to their optimal target structures. Biophysical and biochemical characterization of drug carriers concerning their role as vehicles to carry certain drugs may be obtained using engineering techniques. Manipulation in the cellular sites that cause disturbances in drug delivery is another biomedical option utilized to ensure smooth drug delivery. Various theoretical and experimental techniques are utilized to address all these issues related to drug carriers. The collected chapters written by experts in the field will help the subject matter be understood thoroughly.