Della, Anne and Christine - thank you very much for your kindness.
And Christine - tricky question! Which book first? I guess it depends what sort of information you require initially.
If you want to learn more about all Carnival Glass - where the inspiration behind the designs came from, who the various makers were and their histories, as well as how Carnival is made, then the first one (Carnival Glass The Magic & The Mystery) will be the best. One main section (Patterns) is themed by design motif eg. Flowers, Fruits, People etc. There's also a look at Australian Carnival and an overview of European (to publishing date).
If you want to know more about the European Carnival makers, and have a full (to the publishing date) A-Z of most European patterns by maker, then the second one (A Century of Carnival Glass) is best. Note that this one also covers Carnival made in India and S. America as well as Europe. There is also a section on Late Carnival and another one on the Contemporary makers eg. Mosser, Fenton, Summit etc.
If you want to learn more about the Shapes of Carnival, and the terminology, then the third one (The Art of Carnival Glass) is the best. It also covers the making of Carnival, colours, decorating etc. The book is set out by Shape - so the chapters are on bowls, plates, vases....etc., etc., etc. All countries are covered - so there is glass from the USA, Europe, Australia, India etc.
I hope this personal slant helped a little. If not, let me know.
Thanks again.
Glen