For the benefit of newcomers, old comers and anyone else, here are some links and references to primary sources, rules commentary books and rules apps and e-books.

This is an updated version of the original post.  Links current as at 1 November 2017, but regrettably some of them may not be durable.

Primary Sources

Racing Rules of Sailing

http://www.sailing.org/tools/documents/WorldSailingRRS20172020-[20946].pdf

Racing Rules of Sailing Changes and Corrections (WS version of RRS is not continuously updated [yet])

http://www.sailing.org/tools/documents/RRS20172020changescorrections-[21449].pdf

Racing Rules of Sailing, Study Version with links to the background submissions for all changes made in 2013

http://www.sailing.org/tools/documents/StudyVersionoftheRacingRulesfor20172020Final-[13380].pdf

The World Sailing Case Book (Updated 2017)

http://www.sailing.org/tools/documents/20172020WorldSailingCaseBookv1.1-[22915].pdf

World Sailing Q&As

http://www.sailing.org/raceofficials/qandaservice/doc_list.php

RYA Appeals Book Congratulations RYA for getting the 2017 Appeals Book out when the 2017 rules commence.

http://www.rya.org.uk/SiteCollectionDocuments/Racing/RacingInformation/RacingRules/RYA%20Case%20Book%2003.17.pdf

RYA Rules Guidance Book (As well as guidance on Rules Disputes and Rule 69, includes, at pp 18 to 24, a summary of 2017 rules changes)

http://www.rya.org.uk/SiteCollectionDocuments/Racing/RacingInformation/RacingRules/RYA%20Racing%20Rules%20Guidance%20Book%20-%2012%2016.pdf

These electronic versions are particularly useful because they enable you to electronically search for relevant words or phrases.  You might find it useful to download them so you don’t have to go on-line to see them.

The RRS and the WSCasebook are binding.

The RYA Appeals, although they will nearly always be followed in the UK, are, strictly speaking, not binding.

The Q&A are advisory only, but can be very helpful.

The Definitions in the RRS are critically important:  you need to read and understand them, and, if you have a memory like mine, constantly refer to them as you apply the rules.

The Casebook Section 1 contains Abstracts of Cases by Rule Number.

The RYA Appeals Book Section 2 is similar but it contains both RYA Appeals AND ISAF Cases.

The RYA Appeals Book contains a very useful table, listing all the rules, showing alongside them the relevant ISAF Cases and RYA Appeals.

The RYA Appeals Book is, therefore the easiest one to work from initially, but, as any law student will tell you, don’t rely on the head-notes, and once you have located a relevant Appeal or Case, look at the full version in the Appeal book or the Casebook, and, if in doubt, look critically at other relevant appeals and cases.

US Sailing Appeals Book

http://www.ussailing.org/wp-content/uploads/DARoot/Race%20Admin/Appeals/Appeals%20Book%20for%202017-2020.pdf

Rules Commentary Books

(Google for on-line purchase and further information)

You should buy and read at least one.

Paul Elvstrom Explains Racing Rules of Sailing, 2017-2020 Edition

Includes headnotes from WS Cases and cross-references from the rules to the relevant cases, and a short section on changes to the rules.

Already published as at 2 January 2017, so Case references will be to 2013-16 Case Book

Bryan Willis The Rules in Practice 2017-2020

In my opinion, the best rules book for beginners.

 Eric Twiname (channelled by Bryan Willis) The Rules Book

Great British classic, updated for 2017 rules.

 Dave Perry Understanding the Racing Rules of Sailing through 2020

The US Sailing standard work.  Fuller discussions of all the rules.

Comes with cute cartoons (but no toys).

Apps and E-books

World Sailing Rules App (in conjunction with RYA)

http://www.rya.org.uk/projects/publications/Pages/world-sailing-app.aspx

This is an e-book app, delivering RRS, Cases, Call Books, Q&A and RYA Appeals in an integrated e-book, which also delivers the RYA Rules Guidance Book

Price:  GBP 9.99

Racing Rules of Sailing Website

http://www.racingrulesofsailing.org/

This is an excellent non-official website, run by a group of International Judges, which provides easy on-line access to rules, Cases, Calls, Q&A and National Prescriptions plus racing rules forums and a comprehensive on-line regatta protest management system.  Particularly useful for providing direct web-links to individual Cases and Calls in on-line rules discussions.

Diagramming Tools

 Boat Scenario

http://boats.sourceforge.net/pages/Download

Free 1mB program for Windows, Linux etc

Tactical Sailing Solutions (TSS)

http://tss.peronneau.net/

Original RRS diagramming software.  Not free.  Not updated since 2010.

Protestdraw

http://pathealy.com/cpctools/protestdraw/default.html

A very simple free MS Word document with a comprehensive library of boat and course images.