A great resource for new players and not so new players, Harmonica for Dummies, by Winslow Yerxa is an excellent resource.
What sets this book apart from many other beginners books is the breadth and depth of coverage. It goes far beyond simple first position playing and pulls in many styles of music. In addition it gives information on related subjects such as maintenance, tuning and amplification.
If you are looking for a good introduction then this is a great place to start.
You don’t need any music theory but the tabs are also presented with musical notation so you can pick it up as you go if you want to.