As an adult learner I was looking for a selection of easy to play classics with which to practice and to expand my repetoire. This book has a good selection of well known classical pieces. Even at my low standard (somewhere below grade 1) I was able to clunk my way through half a dozen pieces with some even sounding half decent. I recognised most of the pieces in here even though I only have minimal knowledge of classical music e.g. Fur Elise, Blue Danube, Jupiter (The Planets), etc.
The arrangements increase in complexity as you progress but if you're Grade 1 standard I imagine they will all be within your grasp. Out of all the piano books I have, I use this one the most. Highly recommended.