Kei is the first and so far only solo photobook released by Yasuda Kei. The photobook was published by Wanibooks on March 2, 2002. The photography was done by Kunihiro Takuma.
The title of the photobook is taken from Yasuda Kei's first name, Kei.
The photobook shows a casual but elegant side of Yasuda, showing a little of her in her daily life. It contains mostly feminine close ups of her face. The photobook also contains pictures of her from concerts and also a little of her getting ready for her concerts. It also shows her doing some photography herself. The photobook was said to show a more lovely and relaxed side of Yasuda. It was also said that the photo's were taken not far from Hello! Project's studio.