- Mastering Accounting Skills is a clear explanatory text designed for beginners with no prior knowledge or experience of the discipline. The text contains many practical assignments that reflect the assessment requirements of the manual units for OCR (Oxford, Cambridge and RSA) Levels 1, 2, and 3 Bookkeeping and Accounting qualifications. Step-by-step illustrations enable students to gain a real understanding of the principles and procedures of Bookkeeping and Accounting.