These downloads are in the UK Kindle store, for UK customers only. Those who are in the UK and who have kept their US Kindle account cannot get the books without transferring their account to the UK store (a step which appears, for now, to be one that can be repeated, switching between stores at will) and those physically outside the UK are barred from using the UK store (no doubt by IP detection on Amazon's web site). All twelve titles are from the CK-12 Foundation, whose website says that they are "a non-profit organization with a mission to reduce the cost of textbook materials for the K-12 market both in the U.S. and worldwide" and at least one textbook appears to have been partially funded by taxpayers in Virginia. Yet, none of these are available to those of us in the US. All of these are quite large in size (the first one is 36MB and a couple are over 60MB).
CK-12 Trigonometry
CK-12 Foundation's Trigonometry FlexBook is an introduction to trigonometry for the high school student. Topics include: Trigonometric Identities & Equations, Circular Functions, and Polar Equations & Complex Numbers.
CK-12 People's Physics Book Version 2
The People's Physics Book is intended to be used as one small part of a multifaceted strategy to teach physics conceptually and mathematically.
CK-12 Life Science
CK-12 Life Science covers seven units: Understanding Living Things; Cells: The Building Blocks of Life; Genetics and Evolution; Prokaryotes, Protists, Fungi, and Plants; The Animal Kingdom; The Human Body; and Ecology.
CK-12 Geometry
CK-12 Foundation's Geometry FlexBook is a clear presentation of the essentials of geometry for the high school student. Topics include: Proof, Congruent Triangles, Quadrilaterals, Similarity, Perimeter & Area, Volume, and Transformations.
CK-12 Engineering: An Introduction for High School
Introduces engineering techniques and practices to high school students. This book is designed for a broad range of student abilities and does not require significant math or science prerequisites.
CK-12 Earth Science
CK-12 Earth Science covers the study of Earth - its minerals and energy resources, processes inside and on its surface, its past, water, weather and climate, the environment and human actions, and astronomy.
CK-12 Chemistry
CK-12 Chemistry covers Matter, Atomic Structure; The Elements and Their Properties; Stoichiometry; Chemical Kinetics; Physical States of Matter; Thermodynamics; Nuclear Chemistry; and Organic Chemistry.
CK-12 Calculus
CK-12 Foundation's Single Variable Calculus FlexBook introduces high school students to the topics covered in the Calculus AB course. Topics include: Limits, Derivatives, and Integration.
CK-12 Biology I - Honors
CK-12 Biology I is a textbook for high school students covering cell biology, genetics, evolution, ecology, and physiology.
CK-12 Algebra I
CK-12 Foundation's Algebra FlexBook is an introduction to algebraic concepts for the high school student. Topics include: Equations & Functions, Real Numbers, Equations of Lines, Solving Systems of Equations & Quadratic Equations.
CK-12 Advanced Probability and Statistics
CK-12 Foundation's Probability and Statistics (Advanced Placement) FlexBook introduces students to basic topics in statistics and probability but finishes with the rigorous topics an advanced placement course requires.
CK-12 21st Century Physics: A Compilation of Contemporary and Emerging Technologies
The 21st Century Physics FlexBook is a collaborative effort of the Secretaries of Education and Technology and the Department of Education that seeks to elevate the quality of physics instruction across the Commonwealth of Virginia.