Photographer’s Guide to the Canon PowerShot S100 has been listed for sale at Amazon.co.uk for a few weeks now, but it was not until today that it was listed as being in stock and ready for shipment.  In the meantime, I and one other seller were selling the book as third-party sellers, and Amazon was saying it would ship the book when it became available.  Now, you can order it direct from Amazon and they presumably will ship it fairly soon; the site  says it will ship within 1 to 3 weeks.  If you are interested in ordering the book there, here is a link to the listing of S100 book at Amazon in the UK.