Reddit reviews Man After Man: An Anthropology of the Future

And that's for the paperback!

Edit: oddly, the hardcore hardcover is a lot less valuable

No problem! There was a reprint of After Man in 2018, and it's affordable under $40. Man After Man has indeed been out of print since 1990 and is fairly pricey between $100-300. Dougal Dixon has many other books too such has The New Dinosaurs, If Dinosaurs Were Alive Today, and many other dinosaur related books (many for children.) Most of these are out of print as well and are expensive, but worth it if you're really interested. Maybe you could luck out at your local library and just rent them.

There is however a rare book he made that was only released in Japan for some reason (and of course it's the most badass one) called Greenworld (グリーン・ワールド) about humanity colonizing an alien world and taming certain inhabitants. Although I've never seen Greenworld for sale on English sites, if you know how to order from Amazon Japan you can find the two books in the series for less than $20 a piece.

I linked to some PDF's in my original comment if buying isn't an option.

From the book Man After Man

Reminds me of one of these freaky dudes from the evolutionary futurist picture book, "Man after Man"

It looks as though the image was originally from this book

I am not responsible for the nightmares you're going to have. Let's just get that straight.

The art comes from a book called Man After Man, a horrifying experiment in creativity and futurism. Basically an insane person tried to imagine our next five hundred million years of evolution, spiced up with a few nightmarishly strange choices made by human scientists.

My personal favorite scene is when two Hitek, the near-future human variants who spend 99.99% of their time in life-support creches, attempt to mate.

You should never have asked.

http://www.amazon.com/Man-After-An-Anthropology-Future/dp/0312035608

Go check out this book. It's pure speculation and somewhat dated at this point, but is pretty cool.

http://en.wikipedia.org/wiki/Man_After_Man:_An_Anthropology_of_the_Future

http://www.youtube.com/watch?v=gg562rU4sBc

http://www.amazon.com/Man-After-Anthropology-Future/dp/0312035608

I have another book I would recommend to you. It's called Man After Man. It's pretty pessimistic, suggesting a divide between rich and poor that leads to evolutionary divergence, and also fairly extreme genetic engineering.

http://www.amazon.com/Man-After-Anthropology-Future/dp/0312035608/ref=sr_1_1?ie=UTF8&qid=1422719295&sr=8-1&keywords=man+after+man

I'm not sure how plausible the forms mankind takes in the book are, but you'd probably find it interesting.

Actually, for that matter, you might also read The Time Machine. Probably the earliest book to tinker with the idea (even if the timeline isn't probable). I do think you should be aware that people are starting to tamper with gene therapy and other genetic treatments - if such things ever become advanced enough and commonplace enough, you wouldn't have to worry about a proliferation of such issues in the extreme long term of humanity's future.