I used this textbook in an introductory probability class taught by an outstanding biostatistics professor who has used this edition since publication in 2008.  The professor’s very well developed class notes were the most important resource.  Wackerly’s text book was an excellent adjunct, especially because of the homework problems.  The problems ranged from direct takeoffs from examples in the chapter, to difficult problems that introduced new principles as extensions of the chapter material.  The professor posted homework answer keys with solutions, so the homework was valuable.<br><br>Be cautious if you buy the international versions of this book.  Although the chapter material is supposed to be the same and the international paperback costs substantially less, the order/numbering is slightly different for some homework problems.  My professor pointed out the numbering discrepancies for our assigned problems, but a less experienced lecturer may not be aware of this.<br><br>Order the book as early as possible.  I ordered on the 1st day of class and got the hard copy edition, but many classmates had to order the paperback from other sources.