It is possible to get to know Dublin without a guided tour, but to really get to know the history behind the buildings and to get a taste of the life and history of Dublin, you need a local to tell it to you. Even though the history is full of oppression, battles and failures, the guides tell it with a smile around their mouth, and they are so proud to be Irish. At the same time a guided tour gives you the chance to get recommendations from the guide, ask questions and get more information than any guide book can ever give you.
There are several tours available in Dublin, and here you will find recommendations for some tours available. If you click the links you will be forwarded to either Viator or AttractionTix from where you can book your tickets.