In a nutshell: The author teachers the readers everything they need to know to get started.
Typically aimed at those who know little about the subject, books using the Topic 101 approach present a survey of an idea or situation, and point to resources for further study.
The Topic 101 approach is used in many books belonging to the popular Dummies series, teaching readers about investing, small business, personal finance, penny stocks, marketing, starting a business, and many other business topics.
The Table of Contents for Investing for Dummies illustrates this approach. The book is divided into five parts, each of which is broken down into several sub-chapters. The parts include: investing fundamentals; stocks, bonds and Wall Street; growing wealth with real estate; starting or purchasing a small business; investing resources; and three lists of tips at the end. The book includes just about everything a would-be investor needs to know.
Topic 101 books are meant to be introductory courses in a particular subject. The difference between Topic 101 and The Encyclopedic Approach has to do with the target audience. For Topic 101, readers are assumed to be relative novices in the subject matter, while in The Encyclopedic Approach, material is geared to those already knowledgeable about the topic who can benefit from further explanation and resources.
Continue reading entries in the “Approaches to Writing Business Books” blog series.
 Eric Tyson, For Dummies, 2014.