Welcome aboard npj. I think you mean Gaston Lenotre.
I use several book sellers, including Amazon (who should be sending me a Christmas present for the business I have given them this year).
For older, out of publication books, I generally prefer to use abebooks.com. But Amazon is just fine.
As far as a history of cooking, wow. Have a number of books dealing with the cooking of various periods, from the medieval to the relatively recent, but a comprehensive text, no. Sorry, no ideas.
It seems to me that such a tome would be a lifelong work. First of all there are, to simplify, the Western and Asian cuisines. And then one must sub-categorize. Seems like a daunting task to me. One to my knowledge has not been done.
Perhaps you could ask your girlfriend to be a bit more specific.
Sometimes people ask for something, knowing what they want, but do not define it well enough for someone to respond.
Sorry if this is not more help.
Be honest with her, she will appreciate your efforts.
And may you both have a very Merry Christmas.