Absolute Sudoku

Masha Zager's new puzzle book was recommended to me by a Sudoku guru. I have never tried these puzzles but after seeing everybody on the train toiling away, I thought okay, I'll try. I'm thrilled with this book. The introduction was so informative and clear. Not just "how to" but "how come" and now a new hobby for me and hopefully a few more brain cells will stick a round a little longer than they otherwise might have. Hats off to this author for such an incisive and challenging string of puzzles. Where is volume II?