The Oxford Dictionary of Quotations by Subject (Oxford Paperback Reference) is a handy, compact resource to have around. I think it is far superior to The Merriam-Webster Dictionary of Quotations, which I have been using up until this point.
The entries are arranged alphabetically by subject. Whenever possible, the name of the author, their dates, their significance, the title of the source, and the date of the quotation are given. For example, the fourth quotation under "education" is "Go to the pine if you want to learn about the pine" Matsuo Basho 1644-94 Japanese poet: Nobuyuki Yuasa (ed.) Basho. The Narrow Road to the Deep North (1966) Introduction.
WHY DO I PREFER IT OVER MERRIAM-WEBSTER?
It draws on sources from several traditions (not enough for my taste, but better than most). I think this was a very good choice for an audience that is becoming increasingly familiar with various cultures. In contrast, the content of the Merriam-Webster dictionary is taken almost entirely from the Western one.
It not only gives you the author's name, but enough information to understand roughly when the entry was written, and even the source, so you can actually track down the quotation yourself. Finally, an editor of a general work did not dumb it down and carefully recorded the sources to empower us. Merriam-Webster's only tells you the author and source. If you do not recognize the name, you have no idea when it was written, where, and what the author's significance is.
The content is up to date. Entries in other dictionaries tend to all have come from before I was born. I have found some quotations from as recently as two years ago in this book. Of course, there is nothing at all wrong with old, but I think it is better to have a good mix. Merriam-Webster's dictionary was published nearly two decades ago, and because the editors focused on dead white men, it isn't even useful for quotations from the 80s and 90s.
It is inexpensive (paperback). Although Merriam-Webster's costs even less, I think you get more for your money with this one.
It is somewhat larger than Merriam-Webster's. There is a lot of dead space in the book, and they could have easily printed it smaller if they had wanted to.
The Bible quotations are strangely lacking information. Why only put "Bible: St. Matthew"? Personally, I'd like to know exactly where to find it. Merriam-Webster's provides this.
This is a very well-edited volume that far exceeded my expectations for a general dictionary of quotations. I highly recommend it.