[EDIT] Expanding on the reasons for reading "Life inside a Cluster"

Author: clintongormley

020_Distributed_Cluster.asciidoc

@@ -3,10 +3,18 @@
 
 .Supplemental Chapter
 ****
-As mentioned earlier, this is the first of several "supplemental" chapters about
-how Elasticsearch operates in a distributed environment.  It is useful and
-interesting data, but feel free to skip it.  You can use Elasticsearch for
-a long time without worrying about shards, replication and fallover.
+
+As mentioned earlier, this is the first of several ``supplemental'' chapters
+about how Elasticsearch operates in a distributed environment.  In this
+chapter we explain commonly used terminology like _cluster_, _node_ and
+_shard_, the mechanics of how Elasticsearch scales out, and how it deals with
+hardware failure.
+
+Although this chapter is not required reading -- you can use Elasticsearch for
+a long time without worrying about shards, replication and fallover -- it will
+help you to understand the processes at work inside Elasticsearch. Feel free
+to skim through the chapter and to refer to it again later.
+
 ****
 
 include::020_Distributed_Cluster/00_Intro.asciidoc[]

020_Distributed_Cluster/00_Intro.asciidoc

@@ -8,10 +8,10 @@ add more nodes to the cluster and to spread load and reliability between them.
 
 With most databases, scaling horizontally usually requires a major overhaul of
 your application to take advantage of these extra boxes. In contrast,
-Elasticsearch is _distributed_ by nature. It knows how to manage multiple
+Elasticsearch is _distributed_ by nature: it knows how to manage multiple
 nodes to provide scale and high availability.  This also means that your
 application doesn't need to care about it.
 
-In this chapter we are going to look at how a cluster uses nodes and shards to
-scale with your needs and to ensure that your data is safe from hardware
-failure.
+In this chapter we are going to look at how you can setup your _cluster_,
+_nodes_ and _shards_ to scale with your needs and to ensure that your data is
+safe from hardware failure.