Since their introduction into Canada’s postal system in 1992, Inkjet or Spray-on cancellations have provided collectors with several new specialty areas to enhance their collecting interests. For those interested in postal mechanization these cancels provide a great deal to study, ranging from the types of inkjet printers put into use to their association with Multi Line Optical Character Reader machines used for the sorting and cancelling of mail and the arrangement of the printing heads themselves.For postal history collectors, the introduction of new inkjet printer cancellations provides additional opportunities to record early and late dates of usage and the movement of MLOCR machines within the postal system. For about ten years Canada Post used an array of slogan cancellations that re-vitalized interest in this collecting specialty. The ease with which inkjet cancellations are programmed has led to a myriad of spelling, date and composition errors that are eagerly sought by collectors. Certainly there are many more yet to be discovered. The ease with which errors occurred and the potential embarrassment to Canada Post resulted in the termination of local slogans as well as national slogans except for a HOHOHO Santa slogan used during the Christmas season and a few Canada Post service slogans. Those interested in the hunt have found inkjet collecting a fascinating specialty.This 3rd edition of the Canadian Inkjet catalogue lists over 2300 distinct varieties along with thousands of minor variations. This is an increase of about 900 cancels since the 2001 edition. It provides the collector with the most complete listing of these cancels available. It is the work of many collectors across Canada who have provided information included in the catalogue. An excellent introduction to the catalogue by William Topping provides an understanding of the role of inkjets in mechanized mail sorting and the evolution of the equipment used by the post office.