Book Order

I read a lot of mystery series and am always on the lookout for new ones, or new to me ones. I'm particular in one respect, however. I read my series in order. Accomplishing this feat is sometimes difficult as I get my books from the library. Sometimes other patrons have the books I need and sometimes the library just doesn't have the book. It can be quite frustrating. One thing I've started to see, which I really like, the words "first in the new series" is sometimes printed right on the front cover. I wish they'd put the order number of each book on all covers.