this book is organized into five parts part "introductiondesign patterns essentially describe how objects can interact effectively this book starts by introducing objects in "introduction to objects,and providing graphical examples that clearly illustrate how the patterns work "visual programming in python,and "visual programming of tables of data,introduce the python tkinter librarywhich gives you way to create windowsbuttonsliststablesand more with minimal complexity "what are design patterns?"begins the discussion of design patterns by exploring exactly what they are part ii"creational patternspart ii starts by outlining the first group of patterns that the "gang of fournamed creational patterns "the factory pattern,describes the basic factory patternwhich serves as the simple basis of the three factory patterns that follow in this you create factory class that decides which of several related classes to usebased on the data itself "the factory method pattern,explores the factory method in this patternno single class makes the decision as to which subclass to instantiate insteadthe superclass defers the decision to each subclass "the abstract factory pattern,discusses the abstract factory pattern you can use this pattern when you want to return one of several related classes of objectseach of which can return several different objects on request in other wordsthe abstract factory is factory object that returns one of several groups of classes "the singleton pattern,looks at the singleton patternwhich describes class in which there can be no more than one instance it provides single global point of access to that instance you don' use this pattern all that oftenbut it is helpful to know how to write it in "the builder pattern,you see that the builder pattern separates the construction of complex object from its visual representationso that several different representations can be createddepending on the needs of the program "the prototype pattern,shows how to use the prototype pattern when creating an instance of class is time consuming or complex instead of creating more instancesyou make copies of the original instance and modify them as appropriate "summary of creational patterns,just summarizes the patterns in part ii