Need a book rec for more positive thinking/outlook

[OKKiddo]

I used to be an absolute optimist--a blind optimist who thought the world was only full of good/kind people and that everything worked out for a reason and nothing was more than you could handle. I have had some bumpy roads in the past and I'm married to an absolute pessimist. I think the combination is finally starting to get me down.

So, can you recommend a book (fiction/nonfiction) that will help me re-train my brain or pep me up? I prefer kindle editions because I lug enough gear around I don't want to toss books in too (and my kindle fire does double duty for kid entertainment too, lol).

[Jupiter]

The secret. It's about how thoughts, good or bad, affect you.

[edurnemk]

The Power of Now by Eckhart Tolle.

[npace19147]

The Alchemist by Paolo Cohelo. I found it very powerful, and it's a quick read.