diff --git a/examples/manual-masterdoc/masterdoc.dj b/examples/manual-masterdoc/masterdoc.dj
index c9b2535..759bbfa 100644
--- a/examples/manual-masterdoc/masterdoc.dj
+++ b/examples/manual-masterdoc/masterdoc.dj
@@ -104,4 +104,11 @@ The `sile` object provides intructions for processing the master document with S
 
 ## Content files
 
-Quite obviously, the `content` array is an ordered list of filenames defining the content of the book.
+Quite obviously, the `content` array is an ordered list of files defining the content of the book.
+
+Those files may be of any type supported by SILE, the document class or loaded packages.[^masterdoc-nesting]
+
+[^masterdoc-nesting]: In particular, you can include a master document in another.
+In that case, though, a few elements only from the nested document are used (namely, the declared
+extra packages and the content files).
+
diff --git a/inputters/silm.lua b/inputters/silm.lua
index 8c95ebd..c10dcd8 100644
--- a/inputters/silm.lua
+++ b/inputters/silm.lua
@@ -196,37 +196,53 @@ function inputter.parse (_, doc)
   if not ok then
     SU.error("Invalid master document (" .. err .. ")")
   end
+  if type(master) ~= "table" then
+    SU.error("Invalid master document (not a table)")
+  end
+
+  -- Are we the root document, or some included subdocument?
+  -- in the latter case, we only honor some of the fields.
+  local isRoot = not SILE.documentState.documentClass
 
   local content = {}
 
-  -- Document global settings
-  if master.font then
-    if type(master.font.family) == "table" then
-      content[#content+1] = Cc("use", {
-        module = "packages.font-fallback"
-      })
-      content[#content+1] = Cc("font", {
-        family = master.font.family[1],
-        size = master.font.size
-      })
-      for i = 2, #master.font.family do
-        content[#content+1] = Cc("font:add-fallback", {
-          family = master.font.family[i],
+  local sile = master.sile or {}
+  local metadata = master.metadata or {}
+
+  if isRoot then
+    -- Document global settings
+    if master.font then
+      if type(master.font.family) == "table" then
+        content[#content+1] = Cc("use", {
+          module = "packages.font-fallback"
+        })
+        content[#content+1] = Cc("font", {
+          family = master.font.family[1],
+          size = master.font.size
+        })
+        for i = 2, #master.font.family do
+          content[#content+1] = Cc("font:add-fallback", {
+            family = master.font.family[i],
+          })
+        end
+      else
+        content[#content+1] = Cc("font", {
+          family = master.font.family,
+          size = master.font.size
         })
       end
-    else
-      content[#content+1] = Cc("font", {
-        family = master.font.family,
-        size = master.font.size
+    end
+    -- FIXME QUESTION: I start too think that main language should
+    -- be class option so that some decisions could be delegated to
+    -- the class (e.g. style overrides in the case of resilient classes)
+    -- Not sure how to behave with legacy classes though...
+    if master.language then
+      content[#content+1] = Cc("language", {
+        main = master.language
       })
     end
   end
-  if master.language then
-    content[#content+1] = Cc("language", {
-      main = master.language
-    })
-  end
-  local sile = master.sile or {}
+
   local packages = sile.packages or {}
   if packages then
     for _, pkg in ipairs(packages) do
@@ -235,63 +251,70 @@ function inputter.parse (_, doc)
       })
     end
   end
-  local settings = sile.settings or {}
-  if settings then
-    for k, v in pairs(settings) do
-      content[#content+1] = Cc("set", {
-        parameter = k,
-        value = v
-      })
+
+  if isRoot then
+    local settings = sile.settings or {}
+    if settings then
+      for k, v in pairs(settings) do
+        content[#content+1] = Cc("set", {
+          parameter = k,
+          value = v
+        })
+      end
+    end
+    if metadata.title then
+      content[#content+1] = Cc("odd-running-header", {}, { metadata.title })
     end
   end
-  local metadata = master.metadata or {}
-  if metadata.title then
-    content[#content+1] = Cc("odd-running-header", {}, { metadata.title })
-  end
+
   -- Document content
+  -- FIXME QUESTION: if not a root document, should we wrap the includes
+  -- in a language group?
   for _, inc in ipairs(master.content) do
     content[#content+1] = Cc("include", { src = inc })
   end
 
-  -- PDF metadata
-  -- HACK: inserted at the very end of the document because (at least in SILE 0.14)
-  -- it introduces hboxes than can affect indents, centering, page breaks and paragraphs...
-  if metadata.title then
-    content[#content+1] = Cc("pdf:metadata", {
-      key = "Title",
-      value = master.metadata.title
-    })
-  end
-  if metadata.authors then
-    content[#content+1] = Cc("pdf:metadata", {
-      key = "Author",
-      value = type(metadata.authors) == "table" and table.concat(metadata.authors, "; ") or metadata.authors
-    })
-  end
-  if metadata.subject then
-    content[#content+1] = Cc("pdf:metadata", {
-      key = "Subject",
-      value = metadata.subject
-    })
-  end
-  if metadata.keywords then
-    content[#content+1] = Cc("pdf:metadata", {
-      key = "Keywords",
-      value = type(metadata.keywords) == "table" and table.concat(metadata.keywords, "; ") or metadata.keywords
-    })
+  if isRoot then
+    -- PDF metadata
+    -- NOTE: inserted at the very end of the document because (at least in SILE 0.14)
+    -- it introduces hboxes than can affect indents, centering, page breaks and paragraphs...
+    if metadata.title then
+      content[#content+1] = Cc("pdf:metadata", {
+        key = "Title",
+        value = master.metadata.title
+      })
+    end
+    if metadata.authors then
+      content[#content+1] = Cc("pdf:metadata", {
+        key = "Author",
+        value = type(metadata.authors) == "table" and table.concat(metadata.authors, "; ") or metadata.authors
+      })
+    end
+    if metadata.subject then
+      content[#content+1] = Cc("pdf:metadata", {
+        key = "Subject",
+        value = metadata.subject
+      })
+    end
+    if metadata.keywords then
+      content[#content+1] = Cc("pdf:metadata", {
+        key = "Keywords",
+        value = type(metadata.keywords) == "table" and table.concat(metadata.keywords, "; ") or metadata.keywords
+      })
+    end
   end
+
   -- Document wrap-up
   local options = master.sile.options or {}
-
-  local tree = {
-    Cc("document", {
+  local classopts = isRoot and {
       class = options.class or "resilient.book", -- Sane default. We Are Resilient.
-      layout = options.layout,
       papersize = options.papersize,
+      layout = options.layout,
       resolution = options.resolution
-    }, {
-      content
-    }),
+    } or {}
+
+  local tree = {
+    Cc("document", classopts, { content }),
   }
 
   return tree