Relevant Search: With Applications for Solr and Elasticsearch

For more in depth reading about search, ranking and generally everything you could ever want to know about how lucene, elasticsearch or solr work under the hood I highly suggest this book. Easily one of the most interesting technical books I have read in a long time. If you are tasked with solving search relevance problems even if not in Solr or Elasticsearch it should be your first reference. Amazon Affiliate Link

1[build_sphinx]
2source-dir = docs/source
3build-dir  = docs/build
4
5[upload_sphinx]
6upload-dir  = docs/build/html