Reddit reviews A Concrete Introduction to Higher Algebra (Undergraduate Texts in Mathematics)

The first one is a logic question. Specifically propositional logic, though if you are interested in logic you could also study basic predicate logic.

The second one could fall into a few overlapping categories, but I might put it into abstract algebra. I found a very good book that I used to self-prepare for a graduate course was this one by Dan Saracino. You may need to go one level more basic depending on your background, in which case i've been told this book is good.