Infectious can occur in any part of our bodies. Those which are easily seen on skin, eyes, or which manifest easily like cough, cold, pain in abdomen, make us aware early and so treatment is taken. The treatment may be local and simple or by medicines prescribed by doctors. There are also deeper infections which are not easily known to the individual person or to others who meet casually. Reproductive tract infections (RTIs) and sexually transmitted diseases (STDs) are such conditions. The reproductive genital organs are covered and some parts are only seen with the help/aid of instruments used by trained doctors. Some of the RTIs/STDs may be self limiting i.e. the symptoms or complaints may be relieved after sometime even without treatment, but the infecting organisms are still present in the person and recur in the same person and remain as chromic infection. Such infections can be passed on to other persons with whom they come in direct or intimate contact. Another important issue is when these infections occur in a pregnant woman and during pregnancy it can pass to or affect the baby and cause long term ill effects/ consequences. Thus, it poses a great public health problem. With this scenario, it is very important to make people aware of such conditions and here the age old saying ‘prevention is better than cure’ is very true. In fact, young boys and girls need to be well informed even before they start having sexual relationships. These topics/issues are being addressed / explained through adolescent programmes conducted by public and private health care groups and institutions. Such information is necessary and should be given earlier before girls and boys reach puberty so that they are well prepared and can protect themselves. Parents and teachers are often not comfortable to address these issues and so other groups of providers need to take this responsibility. This book provides information on RTIs and STDs in a simple way along with figures.