A very basic introduction to Geant4 is presented in Chapter 2, "Getting Started with Geant4 - Running a Simple Example". It is a recipe for writing and running a simple Geant4 application program. New users of Geant4 should read this chapter first. It is strongly recommended that this chapter be read in conjunction with a Geant4 system installed and running on your computer. It is helpful to run the provided examples as they are discussed in the manual. To install the Geant4 system on your computer, please refer to the Installation Guide for Setting up Geant4 in Your Computing Environment.

Chapter 3, "Toolkit Fundamentals" discusses generalGeant4 issues such as class categories and the physical units system. It goes on to discuss runs and events, which are the basic units of a simulation.

Chapter 4, "Detector Definition and Response" describes how to construct a detector from customized materials and geometric shapes, and embed it in electromagnetic fields. It also describes how to make the detector sensitive to particles passing through it and how to store this information.

How particles are propagated through a material is treated in Chapter 5, "Tracking and Physics". The Geant4 "philosophy" of particle tracking is presented along with summaries of the physics processes provided by the toolkit. The definition and implementation of Geant4 particles is discussed and a list of particle properties is provided.

Chapter 6, "User Actions" is a description of the "user hooks" by which the simulation code may be customized to perform special tasks.

Chapter 7, "Communication and Control" provides a summary of the commands available to the user to control the execution of the simulation. After Chapter 2, Chapters 6 and 7 are of formeost importance to the new application developer.

The display of detector geometry, tracks and events may be incorporated into a simulation application by using the tools described in Chapter 8, "Visualization".

Chapter 9, "Examples" provides a set of basic, novice, extended and advanced simulation codes which may be compiled and run "as is" from the Geant4 source code. These examples may be used as educational tools or as base code from which more complex applications are developed.