The Bluebook!, by Barco 2.0: Law Library Reference, University of Pittsburg (with hat tip to William P. Statsky)
The approximate cost for the 20th Edition is around $30. If you buy it online to get the free month of the Bluebook Online, it will cost $38.50: https://www.legalbluebook.com/Purchase/Products.aspx?op=Book.
You will find the changes made to the 20th Edition at the beginning of the book. Each new edition provides this information to allow you to see up front to show what has been revised and added to the book.
I am glad to see that this Edition of the Bluebook is addressing the problem of link rot by using Perma.cc. I’ve blogged previously about Perma.cc. I used it exclusively on this blog for a time until more than one posts were lost because the link no longer worked. Perma.cc is still the best tool available now to address link rot. Let’s hope that it works out its reliability problems. -CCE
The 20th Edition of The Bluebook is now available. For this edition, when you purchase a printed copy of The Bluebook, you will get a FREE 30 day trial to the Bluebook Online; look for your free trial key on the back of the title page. The Bluebook for iPad, iPhone and iPad Touch are available via the Rulebook app in the App Store. Perma.cc is pleased to see that this Bluebook now recognizes Perma.cc as a reliable tool for preserving internet sources. . . .