What is the difference between distillation, distillation under reduced pressure and steam distillation ?

Explanation

Simple distillation is used for the purification of those liquids which boil without decomposition and contain non-volatile impurities. Fractional distillation is used for the separation of a mixture of two or more liquids whose boiling points do not differ much. Distillation under reduced pressure is used for the purification of those organic liquids which decompose at their boiling points. Simple distillation is not useful in such a case. Steam distillation is used to purify those organic liquids which decompose at their boiling points but are steam volatile and insoluble in water.