The good thing about a good bookstore or library isn't finding the book you came in for, it's discovering the book you had to have that you didn't even know existed/you were looking for.
Such discoveries are made by hunting for them. You can go online, through publishers catalogs, or read reviews of books. But that doesn't cover everything published. And is still a hit and miss approach. And holding a book in your hands permits you to thumb through it.
I don't find much at the big barn bookstores (bookstop, barnes & noble, or borders) although 20 years ago Bookstop had books that no other store did (in the era of Walden and Barnes & Noble chains and independent stores).
Now most the chains all stock the same 50 titles in any section.