Read Japanese Today (1969)
I picked up this book ahead of a trip to Japan and I must say it was invaluable. Of course in the time since I got back from Japan I've forgotten everything I learned for lack of use, but I'll come back to this book again before my next trip and pick it all up again! The learning technique makes it easy to understand and quick to pick up on, as well as easy to remember. Romaji spelling guides and pronunciation tips are super helpful as well. If you need to learn kanji fast this is a great way to do it!