Global Systems Science is an integrated, interdisciplinary science course for high school. Each GSS book address a societal issue for which science is needed for real understanding. The series emphasizes interconnected systems, encompassing physics, chemistry, biology, Earth sciences, and social sciences. The newest volume is called A Changing Cosmos - it addresses astronomy through image processing software (as is used in a lot of real astronomical research). I wish I had science materials like this when I was in high school! The first volume introduces the series and the approach. As they describe it:
A New World View introduces the GSS central concept of Earth systems in which everything is connected to everything else. It shows how the Earth has tremendously diverse environments, yet is a single planet that we all call "home." Includes focus on forests and an investigation of life inside a terrarium.
This series comes from the University of California at Berkeley, and it's really great. Since I bought the series on CD in December (PDF version), I've been reading various chapters for fun. They are interesting, clearly written, but never "dumbed down" - the authors assume that readers are concerned and curious citizens of the Earth, and just possibly in high school.
Note: If you order the books and/or CD, you may be eligible for downloadable upgrades, though I'm not sure this applies now that the 2009 editions are available. I bought an earlier version of the CD and was able to download the 2009 versions. They do have extensive web links and other materials to update the books based on current events and scientific developments. They also have teacher guides for all and related software for some of the books in the series. You can also download the teacher guides and free sample chapters here.