This book is primarily intended for people who have some acquaintance with deductive methods in elementary formal logic, but who have yet to study associated philosophical problems. Russell coined the phrase philosophical logic to describe the process whereby sentences are formalized in the language of logic. Most of this book is devoted to problems which arise when attempts are made to formalize English in logical languages. The rest considers the rationale behind this activity. The exercises in the text are designed to encourage readers to contribute their own thoughts to the various problems.