For the last few weeks it is really one book: Favorite Arias from the Great Operas
Many years ago I played the guitar, bass, and piano. None very well. Unable to play by ear I became frustrated and hit a wall. I stopped playing altogether for a few years. Taking time off has allowed me to unlearn much of what I had learned.
Now I am starting from scratch, and hopefully this will prove successful. I have always been a classicist, but never had a good blueprint for learning to play. I believe I have a good map now. I am learning to sight read on the guitar. These are all songs I know. They are simple and tuneful. The book is timeless. Just read the following description of the Gianni Schicchi aria O Mio Babbino Caro
"The tune is the sweetest and most easily remembered - if not the best - in the opera. Tinpan Alley may be expected to seize on it the moment it goes out of copyright. That, however, will not happen until 1974."