Britannica Educational Publishing 
Britannica Guide to Matter [PDF ebook] 

The study of matter is the study of all material things, as well as their ability to transform from one state to another. All matter assumes one of several basic states-solid, liquid, gas, and plasma being the most common. Under varying conditions, each state can be altered to form new substances or adopt new characteristics. This insightful book covers the various structures and elements of different types of matter, while examining the physical and chemical properties that allow for permutation and change.