The fundamental idea that this book brings is a bottom-up approach to design. Rather than trying to come up with a big picture and then decomposing it into its individual pieces, this book advocates a recursive style of decomposition then organization.
This book will also stress a method of design. Too often we lock ourselves in a meeting room for a period of time with a blank white board in hopes that by constant discussion all intricacies of the design will be uncovered. This book stresses that the act of design is just as important as the design artifact.