Re: Transparent Power
Although it is not an instructional book, I think its worth buying to
1) Understand that there were others besides Ueshiba with Aiki / additional historical information about training with Takeda in the pre-war years.
2) garner some descriptions of how Aiki feels
3) understand the importance of training beyond just waza in the dojo (i.e. solo training) to generate Aiki. Sagawa Sensei could still do a thousand(?) push-ups when he was in his 70s and 80s
4) Hints of training methods
Ask why a 5th Dan Aikidoka who studied under Yamaguchi Sensei would drop everything to train with Sagawa. If Yamaguchi is one of the greats what did Sagawa have that he didn't have.
Regardless I also think it is a fun read about his life, even if he comes across as arrogant and a misanthrope.