I'm not sure when this was published in relation to the treasury of knitting patterns, but many of these lace patterns are featured in the other two books. However, it is nice to hae a volume solely dedicated to lace motifs and stitches.
Besides some fantastic quotes from Barbara Walker, there is not a lot that I need to say about this book. I do not know exactly how many lace patterns there are, but it certainly a nice selection. I have seen some more recent books (although I unforunately forget the title) that have a larger variety of motifs, and that even include charts, but if you come across a copy of "The Craft of Lace Kntiting" it would be worth considering adding it to your personal collection.
Here are my two favorite quotes from the introduction:
"Lace knitting is justly called the 'height of the knitter's art'"
"More than any other type of knitting, lace offers the greatest scope for individual ingenuity and creativity."