"The travels of Sir John Mandeville" tells the story of Mandeville's travels around the then known world in the 14th century. It provides a fascinating glimpse of a medieval world and medieval worldview. World famous are the descriptions of people with only one big foot, or with dog heads, but the book is full of many great little stories, making it a joy to read.
The book did inspire generations of explorers to reach out beyond their realm. Many explorers used Mandeville's book as a source of knowledge in their discoveries of the world. As such, this is one of the more influential books in world history, and is even today used as a source of inspiration for writers. Milton's "The riddle and the knight" and Eco's "Baudolino" are just two examples of recent books triggered by Mandeville's stories that spring to mind.
The writing style is very recognizable as Medieval. The introduction and explanatory notes from C. Moseley are worthwhile reading as well, because they put the story into context and reveal some hidden information and text analysis.
For anybody interested in medieval history and fantasy stories, this is a little gem of a book.