An augmented reality system, comprising a book ; and an entertainment device ; the book comprising: a first page on a first leaf of the book comprising a first fiduciary marker for indicating an orientation of the book to a recognition system; a second page on a second leaf of the book comprising a second fiduciary marker and also a page marker comprising a plurality of segments that are either marked or unmarked to form a bit pattern that encodes the page number as bits, comprising a most significant bit and a least significant bit, for indicating the page number of the second page to the recognition system; wherein the bit pattern of the page marker indicates the page number of the second page to the recognition system in dependence upon the orientation of the book indicated by the first fiduciary marker and the page marker is positioned closer to an edge of the second page than the second fiduciary marker, so as to become visible to the recognition system before the second fiduciary marker as the book is turned to the second page, and wherein the entertainment device comprises: a video input for receiving captured video frames comprising an image of the book; a fiduciary marker recognition processor of the recognition system, the fiduciary marker recognition processor operable to recognise the first fiduciary marker printed on the first page of the book and operable to estimate an orientation of the book based upon the recognised first fiduciary marker; and a page marker recognition processor of the recognition system, the page marker recognition processor operable to recognise the page marker printed on the second page of the book with reference to the estimated orientation of the book as based upon the recognised first fiduciary marker printed on the first page of the book, wherein the page marker comprises a plurality of segments that are either marked or unmarked to form a bit pattern that encodes the page number as bits, comprising a most significant bit and a least significant bit. a first page on a first leaf of the book comprising a first fiduciary marker for indicating an orientation of the book to a recognition system; a second page on a second leaf of the book comprising a second fiduciary marker and also a page marker comprising a plurality of segments that are either marked or unmarked to form a bit pattern that encodes the page number as bits, comprising a most significant bit and a least significant bit, for indicating the page number of the second page to the recognition system; wherein the bit pattern of the page marker indicates the page number of the second page to the recognition system in dependence upon the orientation of the book indicated by the first fiduciary marker and the page marker is positioned closer to an edge of the second page than the second fiduciary marker, so as to become visible to the recognition system before the second fiduciary marker as the book is turned to the second page, and wherein a video input for receiving captured video frames comprising an image of the book; a fiduciary marker recognition processor of the recognition system, the fiduciary marker recognition processor operable to recognise the first fiduciary marker printed on the first page of the book and operable to estimate an orientation of the book based upon the recognised first fiduciary marker; and a page marker recognition processor of the recognition system, the page marker recognition processor operable to recognise the page marker printed on the second page of the book with reference to the estimated orientation of the book as based upon the recognised first fiduciary marker printed on the first page of the book, wherein the page marker comprises a plurality of segments that are either marked or unmarked to form a bit pattern that encodes the page number as bits, comprising a most significant bit and a least significant bit. <EOS>