Practice your Spanish every day for years with just the phrasebooks, and you’re really going to be able to ask someone where the bathroom is like no one’s business. Study only the dictionaries, and you will be able to give any parrot in Latin, Central, or South America a run for its money. Even well-respected services like Duolingo and Rosetta Stone have their limits. The only way to really learn Spanish is immersion. Total immersion via travel or even residency abroad, ideally. And barring that, watching the hell out of movies, telenovelas, and annoying the hell out of waitstaff at your local taqueria.
Still, there’s something to be said for studying the words by themselves, without much context, on their own. It also helps when there are pictures accompanying the words. The “Spanish-English Bilingual Dictionary” does its job, giving words without context, avoiding idioms and phrases (except in a small appendix at the end of the book.) It’s divided into various general sections, which helps with quick reference and organization. If you want to know the word for keyboard (teclado) it’s under “Work” (Trabajo.) You want to know how to say, “ping pong ball,” (pelota de ping pong) it's under “Sports” (Deportes.) If you want to tell someone what to do with said-ping pong ball, you should really reevaluate why you’re travelling abroad, and understand that sex tourism is not a victimless industry. Recommended.