diff --git a/conservancy_beancount/books.py b/conservancy_beancount/books.py
index 199b922d785ba9148edffa6a3af6d3541460d441..002f7ad4cdeb38e42e5b2757a695c0a91b479e04 100644
--- a/conservancy_beancount/books.py
+++ b/conservancy_beancount/books.py
@@ -110,54 +110,39 @@ class Loader:
           load for a given date range.
         """
         self.books_root = books_root
-        self.opening_root = books_root / 'books'
         self.fiscal_year = fiscal_year
 
     def _iter_fy_books(self, fy_range: Iterable[int]) -> Iterator[Path]:
-        dir_path = self.opening_root
         for year in fy_range:
-            path = dir_path / f'{year}.beancount'
+            path = Path(self.books_root, 'books', f'{year}.beancount')
             if path.exists():
                 yield path
-                dir_path = self.books_root
 
-    def fy_range_string(self,
-                        from_fy: Year,
-                        to_fy: Optional[Year]=None,
-    ) -> str:
-        """Return a string to load books for a range of fiscal years
+    def load_fy_range(self,
+                      from_fy: Year,
+                      to_fy: Optional[Year]=None,
+    ) -> LoadResult:
+        """Load books for a range of fiscal years
 
         This method generates a range of fiscal years by calling
         FiscalYear.range() with its first two arguments. It returns a string of
         Beancount directives to load the books from the first available fiscal
         year through the end of the range.
-
-        Pass the string to Loader.load_string() to actually load data from it.
         """
-        paths = self._iter_fy_books(self.fiscal_year.range(from_fy, to_fy))
+        fy_range = self.fiscal_year.range(from_fy, to_fy)
+        fy_paths = self._iter_fy_books(fy_range)
         try:
-            with next(paths).open() as opening_books:
-                lines = [opening_books.read()]
+            entries, errors, options_map = bc_loader.load_file(next(fy_paths))
         except StopIteration:
-            return ''
-        for path in paths:
-            lines.append(f'include "../{path.name}"')
-        return '\n'.join(lines)
-
-    def load_string(self, source: str) -> LoadResult:
-        """Load a generated string of Beancount directives
-
-        This method takes a string generated by another Loader method, like
-        fy_range_string, and loads it through Beancount, setting up the
-        environment as necessary to do that.
-        """
-        with workdir(self.opening_root):
-            retval: LoadResult = bc_loader.load_string(source)
-        return retval
-
-    def load_fy_range(self,
-                      from_fy: Year,
-                      to_fy: Optional[Year]=None,
-    ) -> LoadResult:
-        """Load books for a range of fiscal years"""
-        return self.load_string(self.fy_range_string(from_fy, to_fy))
+            entries, errors, options_map = [], [], {}
+        for load_path in fy_paths:
+            new_entries, new_errors, new_options = bc_loader.load_file(load_path)
+            # We only want transactions from the new fiscal year.
+            # We don't want the opening balance, duplicate definitions, etc.
+            fy_filename = str(load_path.parent.parent / load_path.name)
+            entries.extend(
+                entry for entry in new_entries
+                if entry.meta.get('filename') == fy_filename
+            )
+            errors.extend(new_errors)
+        return entries, errors, options_map