If one does wish to buy the physical book reprint by Pharr because of the free pdf version available from this website, then there are two ways to read the book from the pdf version.
The first method is rather inconvenient : print the book on paper and read it from there. This is inconvient because of the required printing of the whole book. The style of the books of that era calls for flipping back and forth throughout the pages, as the lesson paragraphs refer to other paragraphs on morphology, syntax and the like. These paragraphs in turn may refer to other paragraphs, etc. So that one cannot read the book on paper without the whole 391 pages available at all times.
The other method is to read the pdf directly from the computer. This is far from a real book, but can present some advantages. However, the available pdf we get does not present such features that make reading a pdf enjoyable.
So here is what I have done with the pdf. First, I have bookmarked the chapters and many of their respective sections. Most of the lessons were bookmarked as well, so one can go directly to them from the standard bookmark panel.
Then I went a step further. At all places were the text refers to a paragraph number, I inserted a hyperlink bringing directly to the desired location, by clicking on the referred-to number. It is simple now to jump all over the book by clicking on the links, and coming back to the original departure point by using the navigation arrow tools of the pdf file.
I do not know if anyone has gone through the trouble of doing this, but it sure makes a big difference in saved time alone. Reading Pharr on my portable computer is now much much more convenient than any piece of paper.