In this chapter the basic design principles and the current state-of-the-art for cutting tools specially designed to be applied on difficult-to-cut materials are described. One by one, the main aspects involved in tool design and construction will be explained in depth over the following sections, completing a general view of the tool world, to provide easy comprehension of the whole book. Materials for the substrates, coatings, and geometry are explained, with special attention to recent developments. A section is devoted to new machining techniques such as high-feed and plunge milling, turn milling and trochoidal milling.