We wanted to provide more materials for professors who wanted them without bogging down those that didn’t. In-text "Web Buttons" allow for more instructor flexibility. These small icons appear throughout the text, indicating additional information on a related subject can be found at our Web site auth.mhhe.com/economics/mcconnellmicro15e/. Instructors can choose to assign all or none of the materials. Types of Web Buttons include:

• The symbol directs students to Analogies, Anecdotes, and Insights. These 50 short pieces, written by Stan Brue, help students understand and remember economic ideas by connecting them to other better-known ideas or easy-to-remember stories and examples.
• The symbol directs students to Origins of the Idea. These brief histories were written by Randy Grant of Linfield College and examine the origins of 68 major ideas identified in the book. Students can learn about the person who first developed such ideas as opportunity costs, equilibrium price, the multiplier, comparative advantage and elasticity.
• The symbol directs students to Interactive Graphs. Developed under the supervision of Norris Peterson of Pacific Lutheran University, these Java applets depict major graphs and instruct students to shift the curves, observe the outcomes, and derive relevant generalizations.

Although most students in the principles course have only modest math skills, a few have taken advanced high school or college courses in mathematics. For the latter group, seeing the algebra and, in a few cases, the calculus behind the economics is highly revealing and useful. Professor Norris Peterson of Pacific Lutheran University has created a Web feature called Do You Want to See the Math? There are 50 math notes that are keyed to the page numbers in the book. They are creative, concise, and will enhance the economics experience for math-minded students.

About one-fourth of the Last Words are new and others have been revised and updated. The new topics include the remarkable organizational ability of markets (Chapter 4); an unusual impact of rent controls (Chapter 7); the economics of criminal behavior (Chapter 7); the positive externalities of antitheft auto tracking devices (Chapter 17); U.S. wealth and its distribution; (Chapter 21); and the struggle for control of capital in Russia (Internet chapter).

The completely updated and revised chapter "Economies in Transition: Russia and China" is available for free use at our Web site. It contains all the features of regular chapters, is readable in Adobe format, and can be printed or read on-screen. Moreover, those who assign this bonus chapter will have a full complement of book supplements to aid in study and testing.

A majority of chapter openers were rewritten for a quicker jump into topics and the entire book was edited with an eye toward cutting extraneous words. Our efforts resulted not only in a shorter book, but in more efficient organization and greater clarity in many places. An example is Chapter 4, which is both shorter and better organized than before. You will find similar kinds of improvements throughout the fifteenth edition. Where needed, of course, the "extra sentence of explanation" remains a distinguishing characteristic of Microeconomics. Brevity at the expense of clarity is a false economy.

We made a number of micro discussions less daunting and more interesting by changing abstract, axiomatic examples (such as X and Y) to concrete examples familiar to students. Also, in keeping with our goal of streamlining discussions, we have consolidated and deleted selected content that was either peripheral to the discussion or was covered in further detail in later chapters.

We realize instructors rarely assign all five micro application chapters (regulation and antitrust; agriculture, income inequality and poverty, labor market issues; and health care economics), but they appreciate the option to select two or three. We gave these chapters particular attention so that discussion of issues is thoroughly updated. For example, Chapter 19 on regulation and antitrust is consolidated and now ends with a new Last Word on the Microsoft case. Chapter 20 on agriculture reflects the recent decline in the prices of some farm products and the renewed debate over the Freedom to Farm Act. The discussion of income inequality in Chapter 21 is reorganized for greater clarity and smoother flow. Chapter 23 on health care reflects the latest data and most current issues.

• Part 1. Chapter 1: Changed terminology from material wants to economic wants; revised discussion of economic methodology, focusing on the scientific method. Chapter 2: Reorganized section on applications; greatly consolidated section on economic systems. Chapter 3: Several new examples including increased demand for coffee drinks, soy-enhanced hamburger as an inferior good, increased supply of Internet service provision. Chapter 4: New chapter title and introduction; revised section on competition to generalize beyond pure competition; consolidation of the Five Fundamental Questions to Four, with discussion explicitly organized around each; briefer chapter. Chapter 5: New chapter title; new terminology: "horizontally organized firms," "vertically integrated firms," and "conglomerates"; new Figure 5-7 on government spending; Chapter 6: New Figure 6-3 showing the types of international flows (trade flows, resource flows, information and technology flows, and money flows); new discussion of the euro; expanded discussion of the WTO.
• Part 2. Chapter 7: Titled changed to reflect chapter content; added application section on cross elasticity of demand; revamped section on government-controlled prices. Chapter 8: Updated applications and extension section; changed language from budget restraint to budget constraint. Chapter 9: Improved explanation of explicit and implicit costs; added "learning-by-doing" to the list of sources of economies of scale; new applications of economies of scale (startup firms and newspapers). Chapter 10: Deleted the section on "Qualifications" to shorten the chapter and because we discuss each in detail in later chapters. Chapter 11: New, updated examples throughout; substantially revised section "Assessment and Policy Options." Chapter 12: greatly shortened the discussion of cartels by focusing on only recent, rather than historical, OPEC actions; changed the identities of firms in the discussion of kinked demand from A, B, C to hypothetically named firms. Chapter 13: Edited down some long lists of examples and added new examples.
• Part 3. Chapter 14: Added Tables 14-5 and 14-6 on occupational trends in the United States. Chapter 15: Transposed the graphs in Figure 15-3; revised discussion of the minimum wage; new Figure 15-9 shows how wage differentials can arise on either the demand or supply side of labor markets. Chapter 16: made the discussion of the single-tax proposal an application of the idea of economic rent.
• Part 4. Chapter 17: Revised Table 17-2 on cost-benefit analysis; integrated the discussion of specific antipollution policies within the analysis of negative externalities; added a brief section on global warming; New Global Perspective 17-1 on carbon dioxide emissions. Chapter 18: Clarified discussion of the payroll tax; inclusion of new CBO (1999) data on average tax rates of all Federal tax sources by income quintile.
• Part 5. Chapter 19: Pared the chapter by eliminating the discussion of industrial concentration and industrial policy; updated examples on antitrust, including the Microsoft case; revised section on industrial regulation for clarity and relevance to today’s regulatory and deregulatory climate; reorganized the discussion of social regulation. Chapter 20: New Figure 20-3 on U. S. farm exports as a percentage of farm output; new Figure 20-4 on which shows inflation-adjusted U. S. agricultural prices for selected commodities, 1950-1998; refocused Table 20-1 from farm population to farm employment; revised he discussion of the Freedom to Farm Act and emergency farm payments 1998-2000. Chapter 21: Reorganized discussion of income inequality and trends in income inequality; new discussion of the decline in the number of people on welfare; new discussion of the inequality of wealth. Chapter 22: Moved this chapter from Chapter 23 in the previous edition. Chapter 23: New issues discussed (patients’ bill of rights, prescription drug coverage under Medicare).
• Part 6. Chapter 24: Shortened this chapter; replaced the discussion of U. S. trade policy with a section on the WTO. Chapter 25: Eliminated the balance sheets in explaining the financing of export and import transactions; updated the discussion of the managed floating system in view of significant bailouts by the IMF and currency interventions by major countries; updated discussion of U.S. trade deficits.