The growing community of Ecological Economists aims to expand the context of economics to include resource and ecosystem service constraints, and broader definitions of human well-being. Despite many academic papers and articles, it hasn't been easy to get an in-depth introduction and overview.
That has been remedied with the publication of not one but two textbooks: Ecological Economics: An Introduction (Michael Common and Sigrid Stagl, 2005) and Ecological Economics: Principles and Applications (Herman Daly and Joshua Farley, 2004). Both discuss many traditional economics topics along with the newer material, and both are well worth reading for perspective on how economic theories can be evolved and updated for the modern world.
The underlying tone is to build up a self-consistent intellectual foundation which respects both economic and natural laws. This includes many insightful theories economists have developed in the past - price elasticity and supply and demand curves work in almost any economic universe. But where contradictions with conventional thinking are particularly evident, the authors show how faulty assumptions have led to mistaken thinking.
In the Common and Stagl book, each chapter ends with a summary, keywords, further reading, discussion questions, and end of chapter exercises - all of which are helpful for direct classroom application or self-study. With its greater length, there are more references, and the writing style tends toward shorter subsections and step-by-step development as compared to Daly and Farley's more conversational tone.
Some sections you wouldn't see in most economics textbooks: Energy and Nutrient Flows -- The Carbon Cycle -- Humans in the Environment - Some History -- Economic Growth and Human Well-Being -- Growth as the Solution to Environmental Problems? -- Limits to Markets -- Climate Change -- Environmental Policy Instruments.
Daly and Farley's book has "Big Ideas to Remember" at the end of each chapter. Some of the economic models are more detailed, and more of the authors' personality shows through, such as when they talk about policy implications. There is also a companion workbook, meant for readers to actively think about and work through ideas in the main book.
Some sections you wouldn't see in most economics textbooks: The Nature of Resources and the Resources of Nature -- From Empty World to Full World -- Market Failures -- Beyond Consumption-Based Indicators of Welfare -- Intertemporal Distribution of Wealth -- Capital Mobility and National Policy Levers -- Sustainable Scale -- Pricing and Valuing Nonmarket Goods and Services.
So, which of the two should you read? If you'd like a drop-in replacement for a standard introductory undergraduate economics text, Common and Stagl fits the bill. (It's also worth reading after you read a standard economics textbook, to see where the similarities and differences lie.) For a more conversational tone, or if you have read and enjoyed Herman Daly's work in the past, try Daly and Farley. Best of all, read both!