Are Book and Medium two separate weights?
some suggestions:
Acute and grave placement on the O/o is off.
Quotation marks are too small.
Is J too narrow? t may be a bit top heavy.
Notch at upper right of g and q looks indecisive.
Superior figs too big. I don't think the barred OS one works in this monoline style. The little tie in % also seems out of place. I like the idea of oldstyle-height %, but it gets awfully wide.

Thanks, Craig-

This started as a Medium, but I then decided it to be Book weight.
You're righ; fixing those acutes and graves.
And I'll look into those J and t.
And right again; those need more depth. I'll definetily fix those to compliment p.
And I believe I have to go through your other commets as well, since they seem to make sense to me. But like I said, I only strated this last weekend, and really only got in touch with the overall feel of the font, so this is still in a design study stage, rather than a final product.

Thanks again.

Looks nicely sober - if predictable. Reminds me of FHWA (AKA Interstate) too. And I like seeing "rationalist" (AKA mirrored) quotes.

I would shorten the descenders. And the spacing is too loose (at least for print). Also, the caps are almost the height of the tittles; I would match the heights.

hhp