Hi Steven,  I checked the default document preferences in UI (no document is open). "Facing pages" is off. See screen shot:  6_DefaultDocPreferences_NoOtherDocOpen.png      With "app.documentPreferences.facingPages = true;" I can change that to "Facing pages: on".  "app.documentPreferences.facingPages = false;" will bring it back to "Facing pages: off".    However, when I do "app.document.add()" or do it's equivalent in UI, InDesign takes the last used document preset to construct a new document.  If the last used document preset happens to be one with option "Facing pages: on", the new doc will logically obtain all properties not included in the script. Therefore an "app.document.add()" only will yield in a document with all properties defined according to the last used document preset.    To change this you can either:  use a different document preset like the default preset "app.document.add(true, app.documentPresets[0])" which happens to be a single pages document by default with a master spread definition of one single page  or try to give all the needed properties and remove master page number two :   var myDoc = app.documents.add();    with(myDoc.documentPreferences){       facingPages = false;       pageWidth = "150mm";       pageHeight = "250mm";       pagesPerDocument = 5;       // ...       };  with(myDoc.viewPreferences){       rulerOrigin = RulerOrigin.PAGE_ORIGIN;       horizontalMeasurementUnits = MeasurementUnits.MILLIMETERS;       verticalMeasurementUnits = MeasurementUnits.MILLIMETERS;       // ...       };  with(myDoc.masterSpreads.item(0).pages.item(0).marginPreferences){       top = "0mm";       left = "0mm";       right = "20mm";       bottom = "0mm";       columnCount = 1;       // ...       };  //I know there might be a "myDoc.masterSpreads.item(1)", but it will never be applied to the doc pages  //Therefore I can delete it. Cautiously I will put that in an if statement:  if(myDoc.masterSpreads.item(0).pages.length>1){          myDoc.masterSpreads.item(0).pages.item(1).remove();          };   With that approach in the beginning my master spread will always contain two pages. I cannot see the possibility to define my master spread to one page only in advance.  Now I tried to implement your suggestion with "app.documentPreferences.facingPages = false;" in front of the code, but it does not influence the construction of the master spread.    One word about "app.documentPresets[0]": I found that it's default after a fresh install of InDesign is "Facing pages: off". However you can edit this later to "Facing pages: on", so my bet is to stay with the solution working only with "app.document.add()", add all necessary properties and remove the needless master page when building single sided documents.    Uwe   
						
					
					... View more