i encapsulated the placenta from dd's birth! i feel like it made a huge difference for me.. i've always been (tearfully, ragingly) sensitive to hormonal fluctuations like pms and with a m/c. i didn't have anything i would consider ppd with dd and the placenta, so i'll absolutely do it again.
even with a c-birth, the hospital didn't give us a hard time at all about wanting to keep it.
for us, the person who encapsulated it had a bit of a hard time, though. she wanted to do it within a week of birth, and we were stuck in hospital. i don't know if it's a state or federal law that it cannot be transported in raw form by anyone other than the owner (LOL) but we had to have a friend sneak it home and the encapsulator friend came and processed it minimally and then took it back to her house to use her equipment to freeze dry. i was super glad to have somebody else do it, though, i wouldn't have been able to, being overwhelmed with a super demanding, difficult-to-nurse screamer.
the placenta person also made prints! so cool! and dried a bit of cord and membrane, put them in special little bags, videotaped a reading of the placenta (like a tealeaf reading) which may be more woo than some services provide, but i thought it was pretty cool.
dd's placenta (i am totally not making this up) was heart shaped and had a big shape in the middle that really looked like a stag. it was the craziest thing and i never would have known it if my friend hadn't done the prints!
then if you read about what the placenta does.. they are so cool, mamas! magic! i love love love it!
eta: i don't know of any books... i learned some from mdc and the google, but if anyone knows of any i'd sure like to read more!