Reddit mentions of Letters from a Stoic: Epistulae Morales Ad Lucilium (Classics)

Why pick and choose when with wikisource you can have them all for free?!

I began with On The Shortness of Life and then bought Letters from a Stoic. I haven't been disappointed yet.

Your friend is not wrong, but he's only half right. He's also framing how one deals with the negative aspects of life poorly. One should do their best to minimize the bad in life, or at least its effects. And, when possible, turn allegedly negative things to one's advantage. One should also do their best to maximize the positive aspects. A lot of it has to do with your perspective and what you focus on.

Everyone has to support themselves somehow. If the only available work is something unpleasant or undesirable, focus on what it affords you and put effort toward getting into a line of work you appreciate more. You can't prevent yourself from ever getting sick, but you can do everything in your power to stay healthy. Healthy eating, an active lifestyle, and getting regular medical checkups all have their benefits. If someone assaults you and you are permanently injured, you're going to have to cope with that, yes. But I'm sure any school worth attending will make accommodations for a student who was assaulted presuming they were made aware of the circumstances.

So, yes, you will have to learn how to cope with the bad things. But you also need to learn how to maximize the positive. Work towards a career you enjoy. Build friendships. Chase your dreams. All that. People tend to write off encouragement and positive thinking, and focus on the negative. But life is what you focus on.

If you struggle with this, I have a few recommended reads for you.

• Victor Frankl's "Man's Search For Meaning". He was a holocaust survivor, and he writes about how even if you take everything else away from a person, they still have the freedom to choose how they react to their circumstances. If prisoners in a concentration camp can find ways to be generous and kind to one another and bring joy and love to each other, so can you.
  
  
• Dr. David M. Burns' "Feeling Good". One of the first books written on Cognitive Behavior Therapy (CBT), it's written in such a way that the reader can apply these therapeutic techniques to their own life. The premise is that our thoughts direct our feelings, and by learning to recognize cognitive distortions and correct our thinking, we can make large headway in dealing with depression. CBT subreddits and posts
  
  
• Seneca "Letters from a Stoic", Epictetus "The Art of Living", Marcus Aurelius "Meditations". Three books by Stoic philosophers. Stoicism was to these ancient Greek and Roman philosophers what CBT is to modern psychologists. These three books contain some of the very best summaries of this school of philosophy. This isn't esoteric, inaccessible philosophy. This is wisdom directly applicable to the very sort of problem you and your friend are dealing with. /r/Stoicism
  
  I know this was an overly long response to your question, but I hope it helps. Learning how to cope well with life is one of the most important things a person can learn. I wish you, and your friend, well.
  
  

The ancient world faced the question of meaning and purpose as much as us. In Marcus Aurelius' writings, I found the perseverance, nobility, and applicable philosophy that I craved after leaving the comfort of Mormonism.

For those who have suicidal thoughts, my primary advice would be to seek out a professional who can assist in working through this very serious time. You can work through it, and you owe it to your future self to persevere.

But as a supplement and a guiding life philosophy, I think Stoicism is a tremendously powerful tool. Perhaps it's not the only tool, but it certainly is one which can form a sturdy basis for weathering the existential stress and anxiety that is common to us all. We must deal with meaninglessness where we once had it clearly spelled out for us. Working through the transitory period of nihilism to something more stable and healthy is possible even within a non-theistic framework. Nature does not require our misery, so why should we be miserable in our existence?

I loved the maxims that are to be found in "Meditations" by Marcus Aurelius and the other Stoic philosophers. Stoicism is a close kin to modern Cognitive Behavioral Therapy, which is used by therapists today, and the richness of the philosophical tradition lends a kind of poetic frame for a full life without self delusion. The stoic concepts are simple, seemingly obvious and easy to become familiar with, but the challenge is in applying them to your life.

If you're truly destitute of meaning and hope, try Stoicism. It helped Vice Admiral James B. Stockdale through his time as a POW in Hanoi, Vietnam for 7 1/2 years - where he was tortured 15 times, placed in solitary confinement for over 4 years, and in leg irons for 2 years. If anyone had a reason for hopelessness, it was him. He later wrote about his experience in "The Stoic Warrior's Triad" and "Master of my Fate", along with "Courage Under Fire: Testing Epictetus' Doctrines in a Labratory of Human Behavior". Imagine facing a seemingly interminable future of misery, but even in this darkness finding something so powerful that you survived and even thrived. That's the power of Stoicism.

In addition to getting a real therapist to work with, and not as a substitute mind you, read "Man's Search for Meaning" and go through the following links, starting at the top and working your way down. By the time you're done, I think you'll have a ready tool to use as you continue on with life outside Mormonism.

The Obstacle is The Way, by Ryan Holiday (a good entry text - don’t skip the reading recommendations at the back)
Letters from a Stoic, by Seneca
Meditations, by Marcus Aurelius (Gregory Hays translation)
The Last Lecture, Randy Pausch (video)
“On the Shortness of Life" Four Hour Blog, Translated by John W. Basore, highlighted by Tim Ferriss
A long podcast conversation with Ryan and Tim Ferriss discussing Stoicism
Achieving Apatheia (slideshare), Ryan Holiday
A lecture series, Marcus Aurelius
The Stoic Life (website about stoicism)
Man in the Arena - Teddy Roosevelt

The Stoics would say pick a few books and master those first, before jumping into a whole bunch of different topics.

So start with the Enchiridion and Discourses and really sink your teeth into it. There's enough in there to last a long time. Read a discourse, think about it, write a summary, pick it apart with examples from your own life, and so on.

Seneca's letters would also be a good read for you at this age:

https://www.amazon.com/Letters-Stoic-Epistulae-Lucilium-Classics-ebook/dp/B002RI99KK/