Study of Songwriting

Thinking about doing some posts about songwriting here. As a teenager, studying songwriting seemed wrong or maybe corny. Still haven't read any books about how to write songs. Are there any you recommend?

Some of the aspects I think of are:

• subject matter
• narrator, point of view
• list songs
• simplicity
• difficulty of performing
• are there lyrics?
• variations (verse, reverse, subverse, inverse, perverse, converse)
• repetition
• metaphor
• tonality
• structure

An exercise of just writing down the forms of a whole bunch of songs

• length of lyrics
• ease of memorization (long and short term)
• biographical
• imitation
• referencing
• bridge
• intro
• outro
• stealing

More soon, I hope.