Computing architectures based on software agents are an important trend in computing technology today. Within such architectures, there are many applications in which planning procedures can play a significant operational role. Planning procedures are characterized by steps of operators that transform an initial state into a desired goal state. This book introduces a graph planning method called "I&G Graphplanner" and a distributed agent architecture called "MAGSIC." I&G stands for Initial and Goal; and MAGSIC is the acronym for the multi-agent architecture that uses situation calculus. The I&G Graphplanner is the reasoning engine of the MAGSIC. The I&G Graphplanner achieves fast speed by solving the problem of explosive operator activations that is associated with forward planners. This book is useful for professionals in task automation, artificial intelligence, or graduate students and professors working on software agents.