Summary
The Enchiridion, literally "in hand" and often translated to "handbook", is an ancient Stoic text written by Epictetus, who was a slave to Nero. It is a collection of thoughts (mostly imperative commands) compiled posthumously by Arrian, one of Epictetus' students. The work is comprised of fifty-three "chapters", which are nothing more than paragraphs dedicated to each topic. The text contains mostly "practical advice" derived from the philosophy of Stoicism, without much in the way of philosophical argument or reasoning behind the advice; it is merely a collection of principles, suggested actions as to how to live a more enlightened and worry-free life.
Subjective Impressions
As a practicing Stoic*, I was beyond excited to read Epictetus. I haven't read his Discourses, but I have read the Meditations of Marcus Aurelius and much of Seneca's Letters of a Stoic, and I've heard that Epictetus is a pleasure to read. Upon investigating the topic some more, I was regrettably told by someone that a person looking to read Epictetus had ought to start with the Enchiridion and read the discourses afterwards. I took their advice, and regret it immensely. The text was entirely unsatisfying to read, it was a complete waste of money and I wish I hadn't even bought it. It's incredibly short; just over 20 pages long, and doesn't really explain why one had ought to do what the text claims.
For example, the eighth chapter says: "Demand not that events should happen as you wish; but wish them to happen as they do happen, and you will go on well." Great, that's all fine and good, but the text doesn't explain why a person had ought to wish for an event to take place simply the way that it transpires. If the text wishes to focus on practicality more than it focuses on abstract ideas and argument, then in my opinion the text should give practical examples as to how the various principles, ideas, and bits of advice can improve one's life. For example, in my writeup I want to eliminate my ego, I don't really go in-depth as to why I believe what I believe, but I do give many practical examples on how a person's life can be improved with the elimination of ego. I want to see the same type of thing in the Enchiridion. If a person doesn't give either a practical reason or an ideological reason, their idea is completely pointless, and arguably meaningless.
There are a few times in which he almost gives a satisfying practical reasoning as to how the enaction of his arbitrary principles can improve someone's life, but then he just doesn't expound or add upon them at all. I spent maybe just under an hour reading the Enchiridion. I would not recommend it at all. Don't waste your time or your money, for that price you can buy a couple of classics off Thriftbooks. You will gain absolutely nothing from the Enchiridion; no new perspective, no interesting ideology or arguments to turn over in your head. I'm sure his Discourses is good, and I'll probably review it once I read it, but all in all the Enchiridion is just not worth the time.
* Capital-'s' Stoic =/= stoic; Stoicism is an ancient school of Roman philosophy, while 'stoic' is a term that means emotional suppression. Stoicism is not about emotional suppression.