My friend's native languages are Cantonese and Mandarin. She rates herself at B1. Peer-reviewed research substantiates that etymology can assist in learning vocabulary. See Google Scholar. English SE has an obvious example.
What books teach English using linguistics like Etymology, Semantics, and Derivational Morphology?
She has been learning English for 20 years. Yet, until I showed her today, she didn't know the semantic shift of "even" as an adjective to "even" as an adverb, or how Latin putare is the root behind "amputate; compute; count ; depute; deputy; dispute; impute; pave; pavement; putative; reputation; repute."
To filter for quality, she prefers authors who are linguists with PhD in linguistics aware of research on L2 Acquisition.