It's easy to print to your local print shop type digital printer for the larger posters but it is much harder to do for offset printing in a illustrative book. Both Ron and Gray use loads of bitmap special effects in their work and these bits would need work for CMYK. The only other way to get round this is to use InDesign CS5 as this is the only programme that I know which could handle it and then export it as PDF X-4 with a coated GRAcOL 2006 colour profile as this has the largest number of colour gamut. Know I don't have Acro Pro CS5 so I don't know if it could be done there but I do have ID CS5.