This is a collection of resources that talk about Solr, or provide case studies of using Solr. People should feel free to add any publicly available information they find about Solr.

Books

Books Specifically About Solr...

• Apache Solr: A Practical Approach to Enterprise Search - by Dikshant Shahi. It covers topics on text-analysis, indexing, searching and scoring in-depth. It also provides learning on integrating semantic capabilities, published by Apress LLC.
• Solr in Action - by Trey Grainger and Timothy Potter. A comprehensive (638 pg.), example-driven guide through Solr 4.7, published by Manning Publications.
• Instant Apache Solr for Indexing Data How-to - by Alexandre Rafalovitch. Covers introductory and intermediate indexing topics for Solr 4.
• Apache Solr 3 Enterprise Search Server by David Smiley and Eric Pugh. This is the 2nd edition of the first book, published by Packt. Essential reading for developers, this book covers nearly every feature up thru Solr 3.4.
• Solr 3.1 Cookbook - by Rafał Kuć (Errata)
• Solr 4.0 Cookbook - by Rafał Kuć (Errata)
• Introduction to Apache Solr (in Japanese) by Koji Sekiguchi, Jun Otani, Yasuo Sanbe, Kouhei Takeda and Takeshi Nakano. This book is an essential guide for Japanese speaking new Solr users.
• Solr 1.4 Enterprise Search Server by David Smiley and Eric Pugh. The first comprehensive resource guide on Solr, written and tested for the 1.4 version.

Other Useful books on Lucene, Text Processing, Search algorithms, etc...

• Lucene in Action, by Erik Hatcher and Otis Gospodnetić
• Lucene in Action, Second Edition, by Michael McCandless, Erik Hatcher, and Otis Gospodnetić
• Taming Text, by Grant Ingersoll and Tom Morton. Chapter on search (using Solr) and also presents "text taming" tools (clustering, Named Entity Recognition, etc.) in the context of Solr.
• Relevant Search, by Doug Turnbull and John Berryman

Product Sheets

• Apache Solr 3.1 Product Sheet (By Cominvent, CC-by-sa license, feel free to edit.)
• Solr flyer (By Lucid Imagination)
• Solr Architecture diagram on Google Docs (By Cominvent, CC-by license)

Articles

• Text Search, your Database or Solr at packtbub (2009-12-01) by David Smiley (a Solr book author)
• Solr: Indexing XML with Lucene and REST at XML.com (2006-08-09)
• An open source endeca? Solr, patacriticism and faceted browsing at biblio.org (2006-05-25)
• Two part series on Solr at IBM developerWorks titled "Search smarter with Apache Solr":
  1. Essential features and the Solr schema (2007-05-29)
  2. Solr for the enterprise (2007-06-05)
• Solr in Libraries A round-up of experimental library catalog projects using Solr from Ryan Eby, (2007-04-26)
• Enterprise search with PHP and Apache Solr at IBM developerWorks (2008-01-15)
• What's new with Apache Solr - Coverage of new features and capabilities in Solr 1.3 by Grant Ingersoll. (2008-11-04)
• Solr Auto-Suggest using TermsComponent and JQuery (by Matt Weber)
  (Published: May 2009 - article)
• Location-aware search with Apache Lucene and Solr - Combine unstructured text and spatial data to enhance your search applications (by Grant Ingersoll)
  (Published: Jan 12, 2010 - article)
• Tips on Loading and Real-Time Searching of Big Data Sets (by Rod Cope)
  (Published: May 17, 2011 - article)
• Data Modeling for Relevance (ideas from Relevant Search by Doug Turnbull & John Berryman)
  (Published: May 15, 2015 - article)
• Sharpening Your Search Results by Improving Relevance (excerpt from Relevant Search by Doug Turnbull & John Berryman)
  (Published: April 2015 - article)
• Efficient Field Value Cardinality Stats in Solr 5.2: HyperLogLog (by Hoss)
  (Published: May 2015)
• Custom Security Filtering in Solr 5.x (by Erik Hatcher)
  (Published: May 2015)
• Solr 5’s new ‘bin/post’ utility (by Erik Hatcher)
  (Published: August 2015)
• Solr as an Apache Spark SQL DataSource (by Timothy Potter)
  (Published: August 2015)
• Securing Solr with Basic Authentication (by Noble Paul)
  (Published: August 2015)
• Min/Max On Multi-Valued Field For Functions & Sorting (by Hoss)
  (Published: September 2015)

Blogs

• Lucidworks Blog - Many of the Solr and Lucene committers blog here about how to use Solr and Lucene
• Search Suggest Functionality
• Sematext Blog - Search and Analytics covering Lucene, Solr, Nutch, Hadoop, HBase, and more
• Cominvent Blog - Articles in Norwegian and English about Enterprise search with Lucene/Solr/FAST
• Solr.pl Blog - Articles in Polish and English about Solr
• OpenSource Connections Blog - Search and Analytics Expertise frequently covering Solr

IRC

• #solr on irc.freenode.net - the Solr community water cooler (web access)

Mailing List Archives

Several third parties provide excellent interfaces for searching/browsing the Solr mailing list archives. Please consider the tips on UsingMailingLists before posting.

• Main Apache Archive: solr-user dev solr-dev (to 2010)
• mail-archive.com: solr-user dev solr-dev (to 2010)
• http://find.searchhub.org/?q=solr - Search the Lucene/Solr ecosystem.
• MarkMail.org: solr-user solr-dev
• Sematext Opensee - https://sematext.com/opensee/ - search the whole Lucene/Solr/Apache/CNCF/... ecosystem.

Media (video, podcasts, etc)

• Solr & Spark for Real-Time Big Data Analytics
  Recorded Webinar: Lucene/Solr Committer Tim Potter presents common use cases for integrating Spark and Solr, access to open source code, and performance metrics to help you develop your own large-scale search and discovery solution with Spark and Solr. (Published: September 2015)
• Simpler Semantic Search with Solr
  Recorded Webinar: Hear from Lucidworks Senior Solutions Consultant Ted Sullivan about how to improve the quality of search results by examining the relationship between language and search. (Published: June 2015)
• Inside Apache Solr 5
  Recorded Webinar: Join Lucidworks CTO and Apache Solr committer Grant Ingersoll for a guided tour of the latest release of Solr. You'll learn about SolrCloud hardening, clusterstate improvements, the schema and solrconfig APIs, easier ZooKeeper management, improved flexible and schemaless indexing, and overall ease-of-use improvements. (Published: February 2015)
• Erik Hatcher discusses Solr on an episode of WebDevRadio here http://www.webdevradio.com/index.php?id=47 (2007-04-10)

Presentations

• Slides from Yonik's Solr presentation at ApacheCon EU 2006
• Subversion and Solr (and Cocoon), your next content repository? Bertrand Delacretaz's presentation at the Cocoon GetTogether 2006
• Slides from Hoss's Faceted Searching presentation at ApacheCon US 2006
• Solr on Rails by Erik Hatcher at RailsConf 2007
• Beyond full-text searches with Lucene and Solr by Bertrand Delacrétaz at ApacheCon EU 2007
• Painless Full Text Search with SOLR by Michael Kimsal at OSCON US 2007
• Apache Solr: Out Of The Box by Hoss at ApacheCon US 2008
  • Older Version of Slides from ApacheCon US 2007
• Introduction to Solr by Tom Hill at eBig Java SIG, June 2008
• Drupal and Solr by Alexandru Badiu at Drupalcon Szeged 2008
• Apache Solr: Beyond The Box by Hoss at ApacheCon US 2008
• Get the most out of Solr search with PHP by Paul Borgermans at PHPBenelux conference 2010
• Key topics when migrating from FAST to Solr by Jan Høydahl at Cominvent AS Lucene EuroCon 2010
• Integration of Apache SOLR with Crawlers by Andrzej Bialecki at Lucene Revolution 2010
• Hadoop + Solr for big data analytics by Ken Krugler at the 2012 Hadoop Summit in Santa Clara.

Products Built On Solr

• Lucidworks Fusion - Use Lucidworks Fusion to make your Solr development and maintenance easy.
• 3RDi - provides solutions for Content Discovery, Semantic Enrichment, Governance, Analytics, Relevancy Management and Automated Testing.

Tip & Tricks

• Posting XML (to Solr) from ant by Peter Binkley (2007-02-01)
• Online indexing - integrating Nutch with Solr by Sami Siren (2007-02-04)

Training

• Lucidworks training - Training on Solr created by Solr committers and contributors (Erik Hatcher, Grant Ingersoll and the rest of the team at Lucidworks).
• SolrTraining.com - Full range of instructor-led public as well as on-site Solr training by Cominvent AS and Jan Høydahl.
• Sematext Solr Training - Solr Training created and run by Sematext's Solr experts - see Core Solr, Intermediate Solr, and Advanced Solr classes.
• DevelopIntelligence - Customized on-site Apache training, with courses on Solr, ActiveMQ, and more.
• Solr Relevance Training - Learn to Think Like a Relevance Engineer from our Solr experts at our regular training courses, including labs & exercises.

Tutorials

• Solr Introductory Quick Start Tutorial - Part of the Solr Reference Guide and a great place to start.
• My Solr - Setting up your first real Solr instance  - Very out of date, I wouldn't go here.