Start with high-confidence a+ certification books, then narrow by subgenre or adjacent topics.
CompTIA Network+ N10-009 Exam Cram
Emmett Dulaney
CompTIA Network+ N10-008 Cert Guide
Anthony J. Sequeira
CompTIA Security+ SY0-701 Exam Cram
Robert Shimonski, Martin M. Weiss
CompTIA A+ Complete Study Guide
Quentin Docter, Jon Buhagiar
CompTIA A+ Certification All-in-one for Dummies
Glen E. Clarke, Edward Tetz
CompTIA CySA+ Study Guide
Mike Chapple, David Seidl
CompTIA Security+ Practice Tests
David Seidl
CompTIA Security+ Certification Kit
CompTIA Linux+ Study Guide
Richard Blum
