Hmmm...very well written, as usual, and touching too.

You contrast Sirius' and James' lives outlooks especially well. 

 Those letters would strengthen Harry immeasurably for his inevitable confrontation with Voldemort.

I have a little trouble wrapping my mind around the thought that James knows about the Prophecy, but hey, that's just my own POV.

Thanks for a great read.

One of the best 'write Harry a letter' ficlets I've seen. Brilliant, absolutely. Your James was a delight to read, and he and Lily were completely real together.

You did need a line break where you switched point-of-views, though. Just a note. But this was great, seriously. Awesome job.