This document summarizes different types of volcanoes and volcanic activity. It describes the composition of magma and why not all mantle rock melts. It defines different types of magma based on their silica content and viscosity. It also outlines the anatomy of volcanoes and describes different types of volcanoes like shield, cinder cone, and composite cone volcanoes. Intrusive igneous features like plutons, batholiths, stocks, sills, dikes and necks are briefly explained. Hot spots and the Hawaiian island chain formation over a mantle plume are also summarized.