I have been playing for about 8 years, mainly as a self-taught musician; the first pieces I learned were a Bach Invention (I think the first one), Mozart's Rondo alla Turca, and Clementi's Sonatina in C.
Alone, it took me months and months, and although the performances left much to be desired, I played at a moderate tempo and in time.
Then something happened.....I began to view the piano as an effort (unfortunately, I believe the difficulty with which I had started ultimately had a negative impact on my motivation). For the following years, I only used the piano to study harmony.
About 3 years ago, I decided to get back into the piano. Once again, I rolled up my sleeves and practiced very slowly, etc. The same thing was about to happen: boredom due to the fact that I was always practicing the same three or four things.
Then, almost by chance, I bought this book, 'Scuola di Pianoforte' (Accademia Lizard), volume 1, by a certain Marco Catarsi, whom I had never heard of. Listening to the many studies from the included CD, a new inspiration sparked in me: I had never before heard a pianist who knew how to play in such a varied quantity of styles: classical, jazz, blues, ragtime, even 60s.
the book 'Scuola per Pianoforte' goes from easy to difficult, so it is progressive.
the book 'Studi Facili' consists of studies that are indeed easy, delightful, for beginners; I will talk more about them below.
However, what struck me about this pianist/composer was his musicality and professionalism. All the pieces are truly very 'tasty' and interesting, there is a lot of versatility, and in my opinion, nowadays it is important to know how to play everything, not just one genre. This book is perfect for that.
(I have also bought many other piano and keyboard books for 'self-taught' players, a lot of them, over the last few years, both in Italian and English; I resold many of them. These Catarsi ones, I am keeping.)
Subsequently, I looked into whether he had published other books, and almost by chance, I downloaded some free pieces from the website of the small publishing company that distributes them, Bianca Edizioni. (I am not putting any links here because I don't know if it's allowed, but you can use Google and search)
They were very easy pieces, but once again, I was struck by the musicality of the pieces, so I bought the collection of easy studies. I wanted to learn these studies for various reasons: as studies on composition, as well as on technique and 'easy' arrangement. It was the first time I had heard pieces that were so easy yet so musical. This author is not just some mediocre person, but a piano master with a lot of knowledge behind him, especially in the field of classical music and for theater.
In short, Marco Catarsi's books have truly inspired me to return to practicing the piano, because the music is truly pleasant and also because there are a myriad of interesting styles, and it is to these people that I recommend these books: those who have started and perhaps lost some motivation, and who need something a bit different from things that are only classical or only jazz, for example.
I highly recommend them also to those who feel 'worn out' by playing too much of the same type of music and want to become a much more versatile pianist (an important goal for me). But naturally, I recommend them to everyone!
You can listen to some of the Studi Facili on Catarsi's YouTube channel; here I put a couple that I like very much:
http://www.youtube.com/watch?v=Yv9tPwLoB3s
http://www.youtube.com/watch?v=zsIj8Yss5vI
well, I just thought I'd point out some interesting books, that's all.