This report from Associated Press:

Book read from in Sex and the City' inspires real life search

NEW YORK (AP) -- A consumer alert for the millions who have seen the feature film version of "Sex and the City": There is no such book as "Love Letters From Great Men," from which Carrie Bradshaw reads while in bed with her beloved Mr. Big.
The closest text in the real world apparently is "Love Letters From Great Men and Women: From the Eighteenth Century to the Present Day," first released in the 1920s and reissued last year by Kessinger Publishing, which specializes in bringing back old works.

Richard Davies, press manager for AbeBooks.com, an online seller that features used titles, told The Associated Press on Thursday that he has received hundreds of queries about the book's existence. Enough readers have been directed to the Kessinger anthology, on AbeBooks and elsewhere on the Internet, that it ranked
No. 134 on Amazon.com as of Thursday afternoon.

In "Sex and the City," an early scene shows Carrie (Sarah Jessica Parker) poring
through the imaginary collection, although citing real letters by Beethoven
and Napoleon among others. Mr. Big (Chris Noth), later takes passages from the
book as he expresses his love, by e-mail, to Carrie.