Anti-cancer agents are the chemicals that are utilized for arresting the growth of cancer cells. These chemicals affect the abnormal growth of cancer cells but they also impact the normal cells such as the cells in the bone marrow, skin, gonads and gastrointestinal tract. Various drugs that are utilized for inhibiting the growth of cancer cells include hydroxyurea, platinum-based drugs and L-asparaginase. Anti-HIV agents on the other hand, are those compounds which decrease the viral load and probability of transmitting HIV to others. Various compounds that are utilized for the treatment of HIV infections include nucleotide reverse transcriptase inhibitors (NtRTIs), and nucleoside reverse transcriptase inhibitors (NRTIs). The NtRTIs are developed to fight virus resistance as they are phosphorylated and require less cellular processing. A significant role is played by secondary metabolites produced by living organisms in the drug development and discovery, as they have biological and structural diversity. They hold the potential for developing anti-cancer and anti-HIV drugs. This book unfolds the innovative aspects of clinical drug research on anti-cancer and anti-HIV agents which will be crucial for the progress of this field in the future. It will serve as a valuable source of reference for graduate and post graduate students.