| The principles and practice of modern surgery
Roswell Park | |
| The Principles of Aesthetics
De Witt H. Parker | |
| The Principles of Biology, Volume 1 (of 2)
Herbert Spencer | |
| The Principles of Biology, Volume 2 (of 2)
Herbert Spencer | |
| The Principles of Breeding / or, Glimpses at the Physiological Laws involved in the Reproduction and Improvement of Domestic Animals
S. L. Goodale | |
| The Principles of Chemistry, Volume I
Dmitry Ivanovich Mendeleyev | |
| The Principles of Chemistry, Volume II
Dmitry Ivanovich Mendeleyev | |
| The Principles of Economics, with Applications to Practical Problems
Frank A. Fetter | |
| The Principles of English Versification
Paull F. Baum | |
| The Principles of Gothic Ecclesiastical Architecture, Elucidated by Question and Answer, 4th ed.
Matthew Holbeche Bloxam |
