Learning French fluently requires a combination of structured study, practice, and immersion. While books are valuable resources, they are most effective when used in conjunction with other learning methods such as language courses, apps, and interactions with native speakers. Here are some highly recommended books to aid in learning French fluently:

"Fluent in French: The Most Complete Study Guide to Learn French" by Frederic Bibard: This comprehensive guide covers all aspects of French language learning, including grammar, vocabulary, pronunciation, and cultural insights. It offers a structured approach to mastering French fluency.

"Practice Makes Perfect: Complete French All-in-One" by Annie Heminway: This book combines comprehensive grammar explanations, exercises, and practical examples to help learners improve their French language skills. It covers all language skills (reading, writing, listening, and speaking) in one volume.

"French Grammar For Beginners" by My Daily French: This beginner-friendly grammar book provides clear explanations of French grammar rules and concepts, accompanied by exercises to reinforce learning. It's an excellent resource for building a strong foundation in French grammar.

"Easy French Step-by-Step" by Myrna Bell Rochester: This book offers a step-by-step approach to learning French grammar and vocabulary, starting with basic concepts and gradually progressing to more advanced topics. It's suitable for beginners and self-learners.
"French Vocabulary Builder: The Complete Study Guide to Learn French" by Frederic Bibard: Building a robust vocabulary is essential for achieving fluency in French. This book provides a comprehensive guide to French vocabulary, including thematic word lists, exercises, and contextual examples.

"French Stories for Beginners: 10 Easy Short Stories with English Glossaries Throughout the Text" by Frederic Bibard: Reading French stories is an effective way to improve reading comprehension and vocabulary. This book features 10 engaging short stories written specifically for beginner French learners, with English glossaries to aid understanding.
"Fluent French: Experiences of an English Speaker" by David I. Bailey: This book offers insights and practical advice from an English speaker who achieved fluency in French. It provides strategies for language learning, cultural immersion, and overcoming common challenges faced by learners.

"French All-in-One For Dummies" by Consumer Dummies: This comprehensive guide covers all aspects of learning French, from grammar and vocabulary to conversation and culture. It's suitable for beginners and intermediate learners looking to enhance their French language skills.