Tha catalogue is a FULL catalogue of the collection, featuring all the items there (ca. 370). It is a very large and heavy volume, a VERY good and professionally written Ottoman arms reference book, that you SHOULD definitely buy, especially if you consider its price.
But please do not think that it will have better or more detailed pictures, or longer descriptions than the smaller English book. In reality, the smaller book features 50 selected objects and has more info and bigger pictures for each of them than in the catalogue. So I think that you should definitely buy both
