Here's a crucial resource for anyone unfamiliar with Library of Congress Subject Headings. This book provides not only their background and history but also their advantages and their limitations. You'll learn the forms of entry, subject heading lists, main headings, compound headings, name headings, headings for literature, art, music, history and law, and subject headings in the online environment.No prior knowledge or experience of subject cataloguing is assumed. This is an indispensable guide to LCSH for practitioners and students alike.
I read this book for my LIS 507 Intoduction to bibliographic metadata class. I think it was pretty helpful in learning about Library of Congress Subject headings, and it comes with great examples, but the only true way to learn about LCSH is to practice assigning them yourself. =) It is a useful start and guide though by introducing all the different subject heading types.