Dusa McDuff & Dietmar Salamon 
Introduction to Symplectic Topology [PDF ebook] 

Over the last number of years powerful new methods in analysis and topology have led to the development of the modern global theory of symplectic topology, including several striking and important results. The first edition of Introduction to Symplectic Topology was published in 1995. The book was the first comprehensive introduction to the subject and became a key text in the area. A significantly revised second edition was published in 1998 introducing new sectionsand updates on the fast-developing area. This new third edition includes updates and new material to bring the book right up-to-date.