I have written a book which is a similar structure to Kathryn Eisman's books - 'How to tell a man by his shoes' and 'How to tell a woman by her handbag'. My question is what category or genre is this? Does it fit into the category of gift books? And if so, do you know any literary agents offhand who represent these type of books?
I don't think these would be gift books so much as lifestyle/humour. When discussing categories one has to remember that they are invented purely for the 18-year-old casual bookshop employee who is not going to look at the cover or read the blurb - they're just going to shelve according to the category (hopefully). So the publisher's marketing department will sometimes kvetch about how they categorise books if the category is not immediately obvious - and even then the pesky teenagers will sometimes wilfully ignore the category anyway. So don't worry about it too much. Let the publisher worry about it for you. As to whether or not agents represent these types of books: it depends very much on the book. If they accept non-fiction submissions of any kind, send it in.