Here is a list of books that were plausibly life-changing for me, personally (link also includes other recommended books). It's too soon to tell if the changes were positive, but I like to believe that they were. 

1. Anathem

2. Famine, Affluence, and Morality

3. Reasons and Persons

4. Animorphs

5. Compassion by the Pound?

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I expect most answers will be non-fiction, and perhaps self-help books

This was not true for me, personally. Self-help books were, for whatever reason, unusually low on the list of books that were life-changing for me, or that I expect to be life-changing for me in the future.

Here's how I justified the list:

The criteria for composing the first list is by trying my best to actually think of books that nontrivially changed my life, rather than books I *wished* had changed my life, or books that I found the most enjoyable, or books that (trying to take the view of a impartial critic) I thought were the "best"/most well-written.

1. Anathem -- I think the other books on this list plausibly have a stronger effect size, but I have the strongest certainty that this book changed me. Various small things in the book's fictional world/alternative social structures stuck out to me, but the largest is the way the book's characters treat news. Many of the characters were cloistered academics (avants), who deliberately and strictly avoided contact with the outside world so they can focus on what's actually important (in the span of decades and centuries, rather than minutes and seconds). Before reading the book, I always felt it's important to "be informed" and "aware" of all the going-ons in the world. I no longer believe this. I now think people (and the world) would be better off focusing on either the very broad (reading philosophy and history and classics from various cultures and other books that will stand the test of time), or the very specific and decision-relevant (ie, latest papers from their chosen sub-specialization, how your best friend or daughter is doing on that very day). And nothing in between.

These days, I block my FB News Feed, actively try to stay away from news websites, and substantially avoid political discussions and gossip (with varying degrees of success).

2. I read FAM in high school. It helped me put altruism (particularly towards LDCs) in the forefront of my thoughts, rather than resting uneasily in the back of my mind. It's unclear whether I would have been drawn to the EA movement without reading FAM (another plausible story is that I would otherwise have gone from Lesswrong -> Givewell to EA even if I didn't major in Econ, or I would have found the online utilitarianism forums somehow while bored).

That said, while there's uncertainty in whether FAM brought me to EA, I think there's less in how important EA is to me. There's a sense in which EA is by far the largest influence on my adult life. EA's directly responsible for me finding my first partner, second job, current house, and probably >50% of my new serious social connections. It's the predominant lens I use to make long-term decisions.

3. I read Reasons and Persons in 2017, so I'm not super sure this book belongs on the list, since it's still "too soon to tell" if the book has a lasting and prolonged effect on me. To the extent it does, the two largest effects are on my views of population ethics (and indirectly, the value of averting existential risks) and personal identity (which I had some unusual opinions on before, but now I feel are more coherent).

4. I can't remember if Animorphs or Magic Tree House were the first English chapter books I read (Age ~ 9). But there's a plausible chance that if I started reading other chapter books, I would have liked them less, and I wouldn't have changed my identity from "lonely Chinese immigrant kid whose father forced him to do advanced mathematics, but otherwise spent most of his time daydreaming" to "lonely Chinese immigrant kid whose father forced him to do advanced mathematics, but otherwise spent most of his time reading." Which is actually a very large change for me.

I don't know if the change was necessarily positive, but I think reading has become such a large part of my identity now (and even more so when I was younger) that it almost doesn't make sense to think of what I would be if I didn't read so much. Because I would be a very different person.

One of the earliest effects on me from spending most of my childhood reading is that my moral center quickly moved towards some vague mixture of late 20th/early 21st liberal American culture with vaguely consequentialist leanings. Which isn't particularly coherent, but was probably more than whatever I had before.

5. I don't know if Compassion by the Pound had a large effect on me. I read it not long before I started working at Impossible, but I think I would have worked at IF anyway. One large update I had from the book is that before reading the book, I thought it was very difficult to have a large impact with research if you didn't go to an elite institution or had other external evidence of being exceptionally talented, since research is so top-skewed. I no longer believe this. It feels naive that I didn't seriously consider this before, but basically all Bailey and Lusk did was rigorously study a subject that wasn't interesting to other economists (animal welfare), but had a huge impact outside of their field (on the welfare of billions of farmed animals). So there's a sense in which people who aren't exceptionally talented can still be exceptionally impactful at research as long as they're willing to work on important but neglected/low-status fields.

Great question. Keen to see other people’s recommendations. We have a list of some of our team’s favorites organized into categories – can be seen on the website here or below. My personal top 5 are Principles, Made to Stick, The Life You Can Save, Algorithms to Live By, and The Lean Startup.

I've got a few:

• GEB
  • Put me on the path to something like thinking of rationality as something intuitive/S1 rather than something I have to think about with a lot of deliberation/S2.
• Seven Habits of Highly Effective People
  • I often forget how much this book is "in the water" for me. There's all kinds of great stuff in here about prioritization, relationships, and self-improvement. It can feel a little like platitudes at time, but it's really great.
• The Design of Everyday Things
  • This is kind of out there, but this gave me a strong sense of the importance of grounding ideas in their concrete manifestation. It's not enough to have a good idea; the effects it causes in the world have to actually have the desired good effects, too.
• Getting Things Done
  • There's alternatives to this, but it made my life better by really helping me adopt a "systems first" mindset to realize that I can improve my life by using systems/procedures and having them well defined and as automatic as possible pays dividends over time.
• The Evolving Self
  • A very dense book about adult developmental psychology. Doesn't necessarily lay out the best possible model of adult psychological development, but it really got me deep on this and set me on a path that made my life much better.
• Siddhartha
  • Okay, one book of fiction, but it's a coming of age story and contains something like suggestions for how to relate to your own life. This one was a slow burn for me: I didn't realize the effect it had had on me until I reread it years later.

I think I've mentioned a few times on the Forum that Strangers Drowning and Doing Good Better have probably been the most influential parts of my EA journey, and I probably wouldn't have been involved in EA without them. Strangers Drowning seemed like a good priming for EA, while Doing Good Better was a pretty compelling intro.

Others, in no particular order:

• The Antidote: Happiness for People Who Can't Stand Positive Thinking was really helpful for improving my thought patterns in a more productive and self-compassionate way.
•  I've used the advice in Change of Heart quite a bit and have seen lots of positive results from it.
• The Defining Decade changed the way I thought about how to develop my career (although it's advice is somewhat similar to 80,000 Hours' talk of "career capital")
• The Renaissance Soul and Quiet were two books that helped me work with certain traits I have that I initially thought were hindering me. 

The Ancestor's Tale got me hooked with trying to understand the world. It was the perfect book for me at the time I read it (2008) because my English wasn't that good yet and I would plausibly have been too overwhelmed with reading The Selfish Gene right away. And it was just way too cool to have this backwards evolutionary journey to go through. Apart from the next item on this list, I can't remember another book that I was so eager to read once I saw what it's about. I really wish I could have that feeling again!

Practical Ethics was life-changing for the obvious reasons and also because it got me far enough into ethics to develop the ambition to solve all the questions Singer left open.

Atonement  was maybe the fiction book that influenced me the most. I had to re-read it for an English exam and it got me thinking about typical mind fallacy and how people can perceive/interpret the same situation in very different ways.

Fiction books I read when I was younger must have affected me in various ways, but I can't point to any specific effect with confidence.

I love this question, and I'm looking forward to reading others' answers! Thanks for asking it! 

The 7 Laws of Magical Thinking: How Irrational Beliefs Keep Us Happy, Healthy, and Sane by Matthew Hutson

I was wrestling with the inescapable thought "I don't want to live as a hypocrite" before I first read it in 2012. I hadn't known becoming more rational was a thing other people knew how to do. Somehow the book's cheerful, mostly forgiving take on how sometimes people are better off irrational gave me the grace I needed to both start seeking ways of mind I could respect in myself, and to appreciate my magical thinking. This book set me up with a growth mindset toward becoming a mind I enjoy. 

Biopunk by Marcus Wohlsen  
This really stretched my imagination about what a single competent person can do. I picked it up for the biology, and ended up thinking about agency, responsibility, risk, and the archetype of the maverick. 

I think I'd have learned this stuff another way if I hadn't read these books. However, these genuinely contributed to me growing in openness, agency, and self-respect.