Clearly written and relatively concise, Simpson's Practical Guide offers just that for teachers and librarians looking to parse the finer points of copyright law. While the focus is largely on K-12 and school libraries, those in higher education and academic/public/special libraries will also find solid guidance here.
Simpson begins with an overview of the law (know thy enemy?), as well as an explanation of the public domain, licensed and royalty-free material, and fair use before launching into chapters addressing the use of specific types of materials (print, audiovisual,music materials, multimedia, software) with a bit about the internet and distance learning crammed in the middle for good measure.
Aside from the repetitive nature of the chapters, which are likely designed with the awareness that some people are only going to read the section they think pertains to their circumstance and not any of the context and thus tend to cover the same points over and over, the only weakness of Simpson's work is its age. The 5th edition was published in 2010, and while that does not render it unusable, it does make you seriously wonder how out of date her coverage of technological issues is. A quick googling reveals at least a couple of touch-ups to the Digital Millennium Copyright Act, and hey, speaking of Google, there may have been a couple of pertinent cases involving them in the last decade that would bear mentioning. So very slight buyer beware: the basics are thoroughly covered here, but there may be recent tweaks (additional exemptions? limitations? who knows?) that happened post-press.
Even with that caveat, Copyright for Schools is fantastically helpful for anyone attempting to navigate the vagaries of fair use. While not precisely scintillating reading, it more than makes up in utility what it lacks in dramatic flair.