I really enjoyed this course. I have listened to many Great Courses and this is so far one of my favourites. I have also been working on my vocabulary in the past year via other audio courses and workbooks, but this has been the most efficacious.
The course begins by teaching various memory techniques for retaining new word meanings. This includes keeping a vocabulary notebook, making personal connections, sound connections, etymological breakdown, and categorization. My main problem is recall, and these are not new techniques, but I have been motivated to employ them to much success.
Lectures are organized by words of a certain category, such as words relating to phobias, words for describing good and bad speakers, words for describing language, toponyms and eponyms, and "grab bags" of miscellaneous words. Professor Flanigan keeps things entertaining by telling the history behind words and memorable personal stories about his friends and family to exemplify key words, ending each lecture with a quiz. He speaks confidently and clearly and is an excellent teacher.
Immediately after finishing this course, I found myself recognizing key words left and right, words that I previously would have only had a vague contextual understanding of and would have thus brushed past. This has been a real confidence booster.
The only downside is, as with all The Great Course audiobooks sold by audible, there is no guidebook. This is a complaint I see by many reviewers of The Great Courses, but if you check out the prices on The Teaching Company's (the makers of TGC) the website in which the guidebook is included, you will see that purchasing them via audible without the guidebook is actually a very good deal. The lack of guidebook is probably the reason audible can charge such a low price without it being a negative for The Teaching Company's overall sales. However, it would have been nice for audible or the Great Courses to at least provide a list of the words, as I had to write them down while listening. Ultimately, being forced to write them down was probably a good thing, as taking notes really helped me to remember the words. Although it did get tricky to confirm the spelling, especially with the more obscure words, but I did manage to find them all with a little googling.
I would also recommend "How To Build a Better Vocabulary" by Maxwell Nurnberg and Morris Rosenblum. I have been working through this in parallel with this course and the words are similar both in selection and difficulty. It's very nice to have learnt a word from one place and have it reinforced elsewhere.