Actually, I love all "Lonely Planet" phasebooks and travel guides. You can't go wrong with them. These are the road warriors in our collection. They are worn, used and helpful! I want to own stock in Lonely Planet!
So you ask, "isn't there a later edition available?" Don't let that stop you. They are using a winning format and when it comes to speaking at least Lithuanian, little has changed (Lithuanian is a really, really, really old language!)
The book is concise and compact (3.5 x 5 x 1/2). It easily fits in any pocket. That is a major selling point. It is the perfect size to take along.
It has an abreviated pronunciation guide compared the single language versions and no dictionary. That comes form having to divide the space between three languages, so it can't go as in depth. Still,all the essentials are here. If you are planning a few days in each place, you'll be fine.
By the way, when you go to the Baltics, look for a copy of the "In Your Pocket Series" available at the airport or in the major hotels. It will be a great help to you. You can also find it online through a simple web search.