I think the book you're looking for is the Directory of Tunes and Musical Themes - Denys Parsons and George Spencer-Brown, 1975. It has about 10,000 classical themes and about 4000 popular songs, classified by the Parson's code(DUR). It is listed as out of print by some sources, but you might look at this German site Directory, which seems to have it for 39 Euros.

Mick