Mixed-valence manganites have attracted considerable attention since the late 19th century. The intriguing interplay of charge, spin and orbital ordering in the manganites systems superimposed by interface/surface effects provides a scientific platform beneficial for both fundamental and application-oriented research. The fundamental basis for understanding physical properties and designing new functionalities of manganites is the concept of the symmetry of order parameters which can be manipulated artificially by controlling the interplay of electronic degrees of freedom. This book explores the possibility of externally modifying the properties of manganite based thin films and heterojunctions by epitaxial strain or artificial boundaries, which could give us new insights to generating properties at the interface between film and heterointerface. The book describes some of the sophisticated concepts concerning manganite-based films and heterojunctions in clear detail, bringing us closer than ever to understanding the research progress and main trends. What we can learn from the book is highly thought-provoking: the explanation of the strain stabilisation and strain induced effects in manganite based films and heterointerfaces; the comparison between electrical transport in manganite based heterojunctions and semiconductor junctions; and, in particular, the interpretation of the photo-induced and photo-voltaic effect in manganite based films and heterojunctions. Furthermore, the magneto-tunability at the manganite based heterointerfaces leading to the design of new functionalities will be highlighted at last.