Queries :: Records Not Showing With Blank Numeric Fields

I have a query which selects a material ID and material name from one table and the associated manufacturer, supplier, and packaging type from three other tables. Some of the manufacturer, supplier, and packaging data were imported from an Excel spreadsheet and did not have data for those fields, so those fields are blank. When I run the query, I only get the records which have all fields filled out. How can I get the records where the material ID and material name are filled in, but the manufacturer, supplier, or packaging type are blank? Here is the query I'm using currently:

Code:
SELECT tblMaterialSpecifications.ID, tblMaterialSpecifications.Critical, tblMaterialSpecifications.MaterialSupply, tblManufacturer.Manufacturer, tblSupplier.Supplier, tblPackaging.PackageType
FROM tblPackaging INNER JOIN (tblSupplier INNER JOIN (tblManufacturer INNER JOIN tblMaterialSpecifications ON tblManufacturer.ID = tblMaterialSpecifications.ManufacturerID) ON tblSupplier.ID = tblMaterialSpecifications.SupplierID) ON tblPackaging.ID = tblMaterialSpecifications.PackagingID
WHERE (((tblMaterialSpecifications.ActiveInactive)=-1))
ORDER BY tblMaterialSpecifications.Critical, tblMaterialSpecifications.MaterialSupply;