The Floer Jungle traces the development of Floer theory while portraying the life of mathematician Andreas Floer (1956-1991), whose ideas transformed geometry and topology. Blending mathematical exposition with biography, it reconstructs the existing ideas, and introduces the main characters, describing their interactions, their judgements and attempts, wrong or right. Aimed at graduate students, researchers, and scientifically curious readers, it emphasizes examples over formalism and offers appendices and references for deeper study. The book is both an engaging introduction to sophisticated mathematics and an intimate portrait of the people who pursue it.