These are the top books I recommend for each subject. I mention a lot of books on this site, but these are the cream of the crop. This list is targeted for home school parents and Christian school teachers, so I include recommended grade levels in parentheses (based on what I consider the ideal age to study the subject). However, these books are useful for all ages! They can be used in churches for study groups or in individual study for adults.
 

History

Western Civilization (9–11)

Western Civilization—Spielvogel


ANCIENT HISTORY (9)

Ancient Greece—Martin
Ancient Rome—Martin


Medieval HISTORY (10)

The Story of Christianity (Vol 1)—Gonzalez


Modern HISTORY (11)

The Story of Christianity (Vol 2)—Gonzalez
Europe—Brendan Simms


AMERICAN HISTORY (12)

The American Pageant—Kennedy
The Politically Incorrect Guide to American History—Woods
 

THEOLOGY

BIBLE (9) 

The Bible
The MacArthur Bible Handbook—MacArthur


SYSTEMATIC THEOLOGY (10)

Bible Doctrine—Grudem
Salvation Belongs to the Lord—Frame


APOLOGETICS (11)

Apologetics: A Justification of Christian Belief—Frame


WORLDVIEW (12)

The Universe Next Door—Sire
Total Truth—Pearcey
 

HUMANITIES

LOGIC (9)

Introductory Logic—Nance & Wilson


PHILOSOPHY (10)

The Consequences of Ideas—Sproul 


ECONOMICS (11)

Economics in One Lesson—Hazlitt
Lessons for the Young Economist—Murphy


GOVERNMENT (12)

The Revolution: A Manifesto—Paul
The Politically Incorrect Guide to the Constitution—Gutzman
The US Constitution
 

Language

LATIN (9–12)

Learn to Read Latin—Keller & Russell 


Greek (11–12)

Basics of Biblical Greek—Mounce
 

Hebrew

Basics of Biblical Hebrew—Pratico & Van Pelt
 

LITERATURE

ANCIENT LITERATURE (9)

Omnibus I (and IV)
Confessions—Augustine


MEDIEVAL LITERATURE (10)

Omnibus II (and V)
The Bondage of the Will—Luther
Institutes of the Christian Religions—Calvin


MODERN LITERATURE (11)

Omnibus III (and VI)
The Westminster Confession of Faith
The Pilgrim's Progress—Bunyan
1984—Orwell

 

MATH

ALGEBRA

???


CALCULUS

???

SCIENCE

BIOLOGY

???


CHEMISTRY

???


PHYSICS

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