The seventh edition of the Drilling Data Handbook was published in 1999. We are in a new millennium and the communication have considerably evolved. The electronic hardware and software allow fast communication anywhere in the world, access to huge databases, as well as permanent refreshing of the documents required by the drilling personnel. At the moment of making a decision about a new edition of the Drilling Data Handbook, the question was: is it pertinent to do an electronic version on a CD support, a web-accessible one with a connection to different sites, or to keep the popular concept of the paper "green book" as people have been using it for decades. The internet gives access to an infinite volume of information but everybody has experimented the trouble of being lost in the way, or the difficulty to reach specific technical information. The Drilling Data Handbook does not want to compete with the web sites of the manufacturers, or other sources of electronic documentation. The main goal of our contribution to the drilling industry is to give access very quickly and without any additional resources to the fundamental data at the office, or at the rig floor. That is the reason why the decision was made to present you this reviewed and updated ninth edition in the formula you are familiar with. and we hope that it will continue to help you when planning and drilling your well.