diff --git a/src/linkml_map/transformer/object_transformer.py b/src/linkml_map/transformer/object_transformer.py
index 973f741..8455f55 100644
--- a/src/linkml_map/transformer/object_transformer.py
+++ b/src/linkml_map/transformer/object_transformer.py
@@ -596,6 +596,9 @@ def _map_value_by_range(
                 if source_class_slot.multivalued and isinstance(v, list):
                     return [self.transform_enum(v1, any_of_enums, source_obj) for v1 in v]
                 return self.transform_enum(v, any_of_enums, source_obj)
+            # No range and no any_of enums: nothing to recurse into for scalars
+            if not isinstance(v, (dict, list)):
+                return v
 
         if source_class_slot.multivalued:
             if isinstance(v, list):
diff --git a/src/linkml_map/utils/dynamic_object.py b/src/linkml_map/utils/dynamic_object.py
index f6752a3..47ae56c 100644
--- a/src/linkml_map/utils/dynamic_object.py
+++ b/src/linkml_map/utils/dynamic_object.py
@@ -3,6 +3,7 @@
 from typing import Any
 
 from linkml_runtime import SchemaView
+from linkml_runtime.utils.formatutils import camelcase
 
 
 class DynObj:
@@ -47,5 +48,7 @@ def dynamic_object(obj: dict, sv: SchemaView, target: str):
         else:
             v = dynamic_object(v, sv, rng)
         attrs[k] = v
-    cls = type(target, (DynObj,), {})
+    # Use camelcase so the Python type name matches ObjectIndex._class_map,
+    # which is keyed by SchemaView.class_name_mappings() (camelcase).
+    cls = type(camelcase(target), (DynObj,), {})
     return cls(**attrs)
diff --git a/tests/test_transformer/test_class_name_spaces.py b/tests/test_transformer/test_class_name_spaces.py
new file mode 100644
index 0000000..7efd77e
--- /dev/null
+++ b/tests/test_transformer/test_class_name_spaces.py
@@ -0,0 +1,130 @@
+"""Regression test for expr with spaces in source class names.
+
+When the source class name contains a space (e.g. "my record"), expr-based
+slot derivations should still be able to access source object fields.
+
+See: https://github.com/linkml/linkml-map/issues/170
+"""
+
+import textwrap
+
+from linkml_runtime import SchemaView
+
+from linkml_map.transformer.object_transformer import ObjectTransformer
+
+SOURCE_SCHEMA = textwrap.dedent("""\
+    id: https://example.org/source
+    name: source
+    prefixes:
+      linkml: https://w3id.org/linkml/
+    imports:
+      - linkml:types
+    default_range: string
+
+    classes:
+      my record:
+        attributes:
+          record_id:
+            identifier: true
+          label: {}
+          source_ref: {}
+""")
+
+TARGET_SCHEMA = textwrap.dedent("""\
+    id: https://example.org/target
+    name: target
+    prefixes:
+      linkml: https://w3id.org/linkml/
+    imports:
+      - linkml:types
+    default_range: string
+
+    classes:
+      Output:
+        attributes:
+          id: {}
+          name: {}
+          source: {}
+""")
+
+INPUT_OBJ = {
+    "record_id": "rec-001",
+    "label": "Hello World",
+    "source_ref": "db:12345",
+}
+
+
+def _make_transformer(transform_spec: dict) -> ObjectTransformer:
+    """Build an ObjectTransformer from inline schemas and a transform dict."""
+    transform_spec["source_schema"] = "https://example.org/source"
+    transform_spec["target_schema"] = "https://example.org/target"
+    tr = ObjectTransformer()
+    tr.source_schemaview = SchemaView(SOURCE_SCHEMA)
+    tr.target_schemaview = SchemaView(TARGET_SCHEMA)
+    tr.create_transformer_specification(transform_spec)
+    return tr
+
+
+def test_expr_with_space_in_class_name_no_index():
+    """expr should resolve source fields when class name has a space (no index)."""
+    transform = {
+        "class_derivations": {
+            "Output": {
+                "populated_from": "my record",
+                "slot_derivations": {
+                    "id": {"populated_from": "record_id"},
+                    "name": {"expr": "label"},
+                    "source": {"expr": "source_ref"},
+                },
+            }
+        },
+    }
+    tr = _make_transformer(transform)
+    result = tr.map_object(INPUT_OBJ, "my record")
+
+    assert result["id"] == "rec-001"
+    assert result["name"] == "Hello World"
+    assert result["source"] == "db:12345"
+
+
+def test_expr_with_space_in_class_name_with_index():
+    """expr should resolve source fields when class name has a space (with index)."""
+    transform = {
+        "class_derivations": {
+            "Output": {
+                "populated_from": "my record",
+                "slot_derivations": {
+                    "id": {"populated_from": "record_id"},
+                    "name": {"expr": "label"},
+                    "source": {"expr": "source_ref"},
+                },
+            }
+        },
+    }
+    tr = _make_transformer(transform)
+    tr.index(INPUT_OBJ, "my record")
+    result = tr.map_object(INPUT_OBJ, "my record")
+
+    assert result["id"] == "rec-001"
+    assert result["name"] == "Hello World"
+    assert result["source"] == "db:12345"
+
+
+def test_expr_string_concat_with_space_in_class_name():
+    """expr with string operations should work when class name has a space."""
+    transform = {
+        "class_derivations": {
+            "Output": {
+                "populated_from": "my record",
+                "slot_derivations": {
+                    "id": {"populated_from": "record_id"},
+                    "name": {"expr": "label + ' (copy)'"},
+                    "source": {"expr": "source_ref"},
+                },
+            }
+        },
+    }
+    tr = _make_transformer(transform)
+    result = tr.map_object(INPUT_OBJ, "my record")
+
+    assert result["name"] == "Hello World (copy)"