The Essentials of Accounting is a good introduction to the basic concepts of financial accounting, presented in an unusual and absorbing format which makes it easy for readers with no existing knowledge of the subject to grasp the fundamentals.
The book consists of approximately 200 pages of prose, outlining various topics, with blanks throughout, which the reader is supposed to complete as they read the text. The correct answers are given at the end of each page. Most of the blanks are for words, but some are for basic calculations. The prose is simple and repetitive, making the book accessible for the most novice of readers. The premise of the book's format is that active reading (i.e., filling-in the blanks), and repetition (i.e., covering the same material at several points in the book) aids retention of the content. Whilst this is certainly true, it does sometimes make the process of reading and completing the blanks sometimes a little laborious. At the end of each chapter there is a brief test, which follows a similar format to the main text. The topics covered include balance sheets, income and cash flow statements, measurement of revenues and expenses and basic analysis of financial statements.
As the title suggests, the Essentials of Accounting is a good primer on the basics of the subject, but no more than this. I read the book as a complete beginner, and found it invaluable in making more advanced texts accessible to me. It is also worth noting that the book is intended for people who review and use financial statements, and not for those who prepare them (although the text does cover the basis processes used in preparing statements).
Overall, this is the best introductory text I have found, and I heartily recommend it. Incidentally, the Essentials of Accounting has been on the reading lists at several top-tier business schools, including Harvard Business School, for several years.