With book search, you need to put exact titles before more popular matches. Amazon used to get this wrong, they don't any more. A telling example is "We" by Zamyatin - a classic, but there are many more recent big sellers with that word in the title, so if exact match is not prioritised, you plain can't find it if you can't remember the guys name. I can't tell if you've got this right - maybe your database isn't big enough for it to matter yet.