title: What's the difference between Jane Street's ‘Base’, ‘Core’ and 'Core_kernel'?
body: <p>I'm new to OCaml, and I it's often suggested that I use Jane Street's standard-library instead of the one that ships with the compiler.</p>
  
  <p>However, there seem to even be several of <em>those</em>, and I don't know which I should be using:</p>
  
  <ul>
  <li><a href="https://github.com/janestreet/base" rel="noreferrer">Base</a>,</li>
  <li><a href="https://github.com/janestreet/core" rel="noreferrer">Core</a>,</li>
  <li>and <a href="https://github.com/janestreet/core_kernel" rel="noreferrer">Core_kernel</a>.</li>
  </ul>
  
  <p>Can anybody quickly summarize the difference between these (and perhaps vs. Batteries, etc), or when and why I should choose one over the others?</p>