From the pieces you mentioned, the two inventions contain what we call 'two-part counterpoint'. However, if you look at much music from the renaissance and early-baroque music, you will encounter a lot of so-called 'contrapuntal' music. This goes for a lot of the romantic music and beyond that ass well, except that in the romantic music the melodies became more and more complicated and composers threw in a lot of difficult passage work. A lot of music from the classical period is mostly a combination of chordal accompaniment in the left hand (bass clef) and melodic playing in the right hand (treble cleff). It's really a question of what kind of piece your studying. I won't be graded by anyone other than myself but it helps with no instruction. My personal goals are 1.) Learn to identify all notes 2 and 3.) Play bachs minuet in g, prelude in c and invention no.1 4.) To learn cgad major.scales by memory and play them backward, forward, hands together, contrary and basically the rest of level one for abrsm. Now I'm focusing on pieces and such because I have found the time. I cannot get lessons I live to far away from anywhere that I can find instruction. Plus I have found it to be a lot.more fun this time around. But I did almost no sight reading before and am more dedicated to it now and can takeit wherever I go so its is convenient to sight read. I got virtually nowhere before other than figuring out some personal goals., and learning about arpeggios and scales. So I didn't really "quit" I more than Anything else put it to the side for awhile. It is not the reason I quit before lol I had to focus on my pregnant wife at the time. I have all bachs inventions and books with music and sight read on those afterwards. Basically adding one note at a time till i can identify it. So say I did that in c octave then I basically move it up a step to the octave of d. I have a program that runs the notes in an octave I cover each till I have it perfect 3x totals about 80 notes or so.