Sure it's free, but for a primer in the field of communication it is not a good presentation.
For example, communication classes typically cover plagarism but this book has images without captions. The images actually hinder the communication of the content because the *distract* from it due to them appearing arbitrary or only tangentially relevant.
Quotes were relevant, and attributed to a person, but unlike what the book recommends about using quotes to build credibility, quotes were offered with no remark on why that person would be someone credible for the topic.
The book was written like a speech, with repetition and "tell them what you will tell them, tell them, and tell them what you told them" not like. book, which is what this is.
And finally, with irrelevant and un-captioned images and filler quotes (worse than what Wikipeda can do) do not list Encyclopedia Brittanica as an unreliable source. Hell, don't call it unreliable at all unless you want to write an essay on why I should believe that. I am just old enough to be on the tail end of encyclopedias and dictionaries counting as what amounts to a first-hand source in terms of reliability; if you raise that point BACK IT UP. That is one of the guidelines even brought up in the book.