I recently had the good fortune of finding this book at a thrift shop: A Decent Cup of Tea by Malachi McCormick (Clarkson Potter, 1991). Actually, the book just jumped off the shelf into my hand after my eye got caught on the word "tea" as it was browsing titles along the shelf.
I say that I had good fortune in finding this book because A Decent Cup of Tea turned out to be a quick and entertaining read. The book gives a synopsis of everything tea - from the history of tea drinking, through making a decent cup of tea, to reading tea leaves. And McCormick's witty way of writing kept me engaged from the first of the book's 79 pages to the last.
My recommendation is to buy this book. It would be a fun addition to any tea book library. And I am glad to have added it to mine.