The Ninth Edition features expanded coverage of electronic sources, both subscription-based (such as Westlaw, LexisNexis, Checkpoint, CCH IntelliConnect, and HeinOnline) and those available without charge (particularly those provided by the government). It discusses factors to be considered in deciding between print and online research; chapters discussing primary sources illustrate several online sources for finding these materials. This book devotes considerable space to publicly available IRS documents and legislative history materials. The introductory materials illustrate solving a research problem, and there are updated problems for students to solve throughout the text. The Ninth Edition expands the number of illustrations that complement its textual discussions. A teacher's manual will be available.