If a pattern sourcebook is what you are looking for, then this one is definitely worth buying. I wouldn't go so far as to say it's the ultimate sourcebook, but with only 1001 motifs, it doesn't maintain to be the ultimate! But if you're a keen craftsperson, you will be able to apply and combine the designs and motifs in this book very easily to a great variety of crafts. I have used these motifs very successfully on papier-mache, wooden blanks, unfired bisqueware and needlepoint tapestry.
The black and white line drawings are quite large and displayed clearly on each page. The are set in chapters according to their national origin (covering designs ranging from Ancient Minoan to Nepal and Afghanistan) and number indexed so that you can tell exactly where the original motif was found - eg an Ancient Egyptian motif found on a box in Tutankhamen's tomb. There is also a chapter covering various ages, ranging from Celtic to the Bloomsbury Group, although in some cases these are a bit sparse - there are only 12 motifs covering the whole of the Art Nouveau and Art Deco movements. In writing, this may seem rather unsatisfactory, but in fact, it does actually give you a good taste for the period. To be fair, MacCarthy has stocked some sections much better than others.
If however you are looking for detailed colour pictures (it is often desirable to know what the authentic colours should be) this book does not provide that sort of information. Each chapter title page is in colour, followed by a few colour photographs of how the motifs might be applied, but that is all. I have found it useful to use the patterns in this book in conjunction with colour information from other sources ( in particular The Encyclopaedia of Ornament by A.Racinet and The Treasury of Ornament by Heinrich Dolmetsch, both published by Studio Editions). Whilst some of the designs in MacCarthy's book are quite complex and will require enlarging, many of them are simple enough to copy freehand.
There is also a chapter on Techniques which covers topics such as enlarging and reducing, needlepoint stitches, beading, applique etc. Each of these is granted three very small paragraphs (after all,this is not a specialised craft book) and merely serve the purpose of showing how the designs can be applied to anything imaginable - and I'll vouch for that.