A Modern Formal Logic Primer: Sentence Logic + Predicate Logic

Freely available online at
+ https://tellerprimer.ucdavis.edu/ (chunked PDF)
+ https://human.libretexts.org/Bookshelves/Philosophy/A_Modern_Formal_Logic_Primer_(Teller) (HTML)

From the first paragraph of the Preface:

"This text is a primer in the best sense of the word: A book which pres-
ents the basic elements of a subject. In other respects, I have sought to write a different kind of text, breaking with what I regard as an unfor- tunate tradition in teaching formal logic. From truth tables through com- pleteness, I seek to explain, as opposed to merely presenting my subject - matter. Most logic texts (indeed, most texts) put their readers to sleep
with a formal, dry style. I have aimed for a livelier lecture style, which treats students as human beings and not as knowledge receptacles. In a text, as in the classroom, students need to be encouraged and to hear their difficulties acknowledged. They need variation in pace. They need shifts in focus among "I," "we," and "you," just as most of us speak in the classroom. From time to time students simply need to rest their brains."