First in two Samurai Film Handbooks by Patrick Galloway. Personally I love this book! I have read his second volume titled Warring Clans and Flashing Blades, which I also loved. Stray Dogs and Lone Wolves is a great introduction to many classic Japanese sword movies, that includes Yakuza and Ninja movies known as Chambara. The introduction is top notch and full of fun and interesting information.
Let it be known that the movies reviewed in this book are classics and many are masterpieces. The Japanese directors that make these masterpieces are on par with Orson Welles, Ingmar Bergman, Stanley Kubrick, and Alfred Hitchcock and the like. Akira Kurosawa is the most famous and is a genius in my opinion. Yet others like Masaki Kobayashi, Kenji Mizoguchi, and Kaneto Shindo are all amazing and brilliant directors and can give any western film maker a run for their money any day. There are no cheesy action flicks reviewed, all are quality cinema. You can't go wrong by following Patrick's advice and start with Yojimbo. If you've seen these movies, the book is a great reference to have on hand for the film enthusiast to go back and read interesting details about each movie. For instance he tells about the camera focus in Yojimbo being clear in the foreground as well as the background to tell visual stories inside each dwelling when the shutters open and close as Sanjuro walks down the seemingly deserted town that is in turmoil due to a feud between Yakuza bosses.
This book is sadly out of print. You may be able to write Stone Bridge Press and request them to reprint it, or may find the author in social media. If not, get Warring Clans and Flashing Blades for an even more in depth introduction to Chambara.