Wear on the edges. Shipped the next business day! We own a small family book store and sell our extra books and media that have been on our shelfs for too long. We sell them for a quarter of the price at our store so we can move our inventory! Additional Details ------------------------------ Product description: This authoritative book, highly regarded for its intellectual quality and contributions provides a solid foundation and life-long reference for anyone studying the most important methods of modern signal and system analysis. The major changes of the revision are reorganization of chapter material and the addition of a much wider range of difficulties.