The weak or non-conventional hydrogen bond has been the subject of intense scrutiny over recent years. Although the existence of this type of hydrogen bond was suggested many years ago, research has traditionally focused on the stronger and more well-known forms of hydrogen bonds. However, a growing body of experimental and theoretical evidence now confirms that hydrogen bonds like C-H...O, O-H..., C-H... and even bonds such as O-H...metal play distinctive roles in structural chemistry and biology. This book provides a critical assessment of this interesting and occasionally controversial...