Below I shall try to express in a few words why I decided to publish this book. I joined Düsseldorf Engineering College (FHD, Düsseldorf) in 1987 as Visiting Professor (Lehrbeauftragter) after working more than 30 years in industries. To prepare myself for my teaching job I had to consult the normal text books available in the market. Professionally I was mostly engaged in process and equipment calculation and I feIt normal text books donot prepare the students weIl enough for their professional requirements. With the introduction of computer our attitude towards Chemical Engineering has changed and probably will go on changing rapidly for quite some time. Instead of finding out an easy solution to a problem, as was the practice before the advancement of computer, we go in for an elaborate and complicated method, because the computer permits us to think in an unlimited way. So I thought of introducing the students not only to basic fundamental knowledge but also introduncing them to unlimited opportunities opened up by computer. For this again applicaltion of mathematics in Chemical Enginnering is an essential knowledge. With this view in mind I prepared my original manuscript and after retiring from Engineering college I revised my original manuscript, included a few items, which are normally not included in curriculum and decided to publish it.