Von Brackel's book is available on Amazon.com for $53
Another good starter book is Paperweights by Sibylle Jargstorf, it covers mainly European makers,
with good examples of Bohemian millefiori weights, the usual French makers, British makers, Murano etc.
If you're interested in US antique weights then Hawley's book on Sandwhich and New England Glass Company is
well worth looking into.