diff --git a/src/openqdc/datasets/base.py b/src/openqdc/datasets/base.py
index 392144d..96e0f0c 100644
--- a/src/openqdc/datasets/base.py
+++ b/src/openqdc/datasets/base.py
@@ -1,7 +1,9 @@
 import os
 from os.path import join as p_join
+from typing import Dict, List, Optional
 
 import numpy as np
+import pandas as pd
 import torch
 from loguru import logger
 from sklearn.utils import Bunch
@@ -18,7 +20,13 @@
 from openqdc.utils.molecule import atom_table
 
 
-def extract_entry(df, i, subset, energy_target_names, force_target_names=None):
+def extract_entry(
+    df: pd.DataFrame,
+    i: int,
+    subset: str,
+    energy_target_names: List[str],
+    force_target_names: Optional[List[str]] = None,
+) -> Dict[str, np.ndarray]:
     x = np.array([atom_table.GetAtomicNumber(s) for s in df["symbols"][i]])
     xs = np.stack((x, np.zeros_like(x)), axis=-1)
     positions = df["geometry"][i].reshape((-1, 3))
@@ -42,18 +50,12 @@ def extract_entry(df, i, subset, energy_target_names, force_target_names=None):
     return res
 
 
-def read_qc_archive_h5(raw_path, subset, energy_target_names, force_target_names):
+def read_qc_archive_h5(
+    raw_path: str, subset: str, energy_target_names: List[str], force_target_names: List[str]
+) -> List[Dict[str, np.ndarray]]:
     data = load_hdf5_file(raw_path)
     data_t = {k2: data[k1][k2][:] for k1 in data.keys() for k2 in data[k1].keys()}
     n = len(data_t["molecule_id"])
-    # print(f"Reading {n} entries from {raw_path}")
-    # for k in data_t:
-    #     print(f"Loaded {k} with shape {data_t[k].shape}, dtype {data_t[k].dtype}")
-    #     if "Energy" in k:
-    #         print(np.isnan(data_t[k]).mean(), f"{data_t[k][0]}")
-
-    # print('\n'*3)
-    # exit()
 
     samples = [extract_entry(data_t, i, subset, energy_target_names, force_target_names) for i in tqdm(range(n))]
     return samples
diff --git a/src/openqdc/datasets/geom.py b/src/openqdc/datasets/geom.py
index 6af826e..eebcc66 100644
--- a/src/openqdc/datasets/geom.py
+++ b/src/openqdc/datasets/geom.py
@@ -1,4 +1,5 @@
 from os.path import join as p_join
+from typing import Dict
 
 import datamol as dm
 import numpy as np
@@ -9,7 +10,7 @@
 from openqdc.utils.molecule import get_atomic_number_and_charge
 
 
-def read_mol(mol_id, mol_dict, base_path, partition):
+def read_mol(mol_id: str, mol_dict, base_path: str, partition: str) -> Dict[str, np.ndarray]:
     """Read molecule from pickle file and return dict with conformers and energies
 
     Parameters
@@ -20,15 +21,18 @@ def read_mol(mol_id, mol_dict, base_path, partition):
         Dictionary containing the pickle_path and smiles of the molecule
     base_path: str
         Path to the folder containing the pickle files
+    partition: str
+        Name of the dataset partition, one of ['qm9', 'drugs']
 
     Returns
     -------
     res: dict
         Dictionary containing the following keys:
-            - atomic_inputs: flatten np.ndarray of shape (M, 4) containing the atomic numbers and positions
-            - smiles: np.ndarray of shape (N,) containing the smiles of the molecule
-            - energies: np.ndarray of shape (N,1) containing the energies of the conformers
-            - n_atoms: np.ndarray of shape (N,) containing the number of atoms in each conformer
+        - atomic_inputs: flatten np.ndarray of shape (M, 5) containing the atomic numbers, charges and positions
+        - smiles: np.ndarray of shape (N,) containing the smiles of the molecule
+        - energies: np.ndarray of shape (N,1) containing the energies of the conformers
+        - n_atoms: np.ndarray of shape (N,) containing the number of atoms in each conformer
+        - subset: np.ndarray of shape (N,) containing the name of the dataset partition
     """
 
     try:
@@ -56,6 +60,22 @@ def read_mol(mol_id, mol_dict, base_path, partition):
 
 
 class GEOM(BaseDataset):
+    """
+    The Geometric Ensemble Of Molecules (GEOM) dataset contains 37 million conformers for 133,000 molecules
+    from QM9, and 317,000 molecules with experimental data related to biophysics, physiology,
+    and physical chemistry. The dataset is generated using the GFN2-xTB semi-empirical method.
+
+    Usage:
+    ```python
+    from openqdc.datasets import GEOM
+    dataset = GEOM()
+    ```
+
+    References:
+    - https://www.nature.com/articles/s41597-022-01288-4
+    - https://github.com/learningmatter-mit/geom
+    """
+
     __name__ = "geom"
     __energy_methods__ = ["gfn2_xtb"]
 
diff --git a/src/openqdc/datasets/molecule3d.py b/src/openqdc/datasets/molecule3d.py
index 0d59400..e5870ca 100644
--- a/src/openqdc/datasets/molecule3d.py
+++ b/src/openqdc/datasets/molecule3d.py
@@ -1,5 +1,6 @@
 from glob import glob
 from os.path import join as p_join
+from typing import Dict, List
 
 import datamol as dm
 import numpy as np
@@ -12,7 +13,26 @@
 from openqdc.utils.molecule import get_atomic_number_and_charge
 
 
-def read_mol(mol, energy):
+def read_mol(mol: Chem.rdchem.Mol, energy: float) -> Dict[str, np.ndarray]:
+    """Read molecule (Chem.rdchem.Mol) and energy (float) and return dict with conformers and energies
+
+    Parameters
+    ----------
+    mol: Chem.rdchem.Mol
+        RDKit molecule
+    energy: float
+        Energy of the molecule
+
+    Returns
+    -------
+    res: dict
+        Dictionary containing the following keys:
+        - name: np.ndarray of shape (N,) containing the smiles of the molecule
+        - atomic_inputs: flatten np.ndarray of shape (M, 5) containing the atomic numbers, charges and positions
+        - energies: np.ndarray of shape (1,) containing the energy of the conformer
+        - n_atoms: np.ndarray of shape (1) containing the number of atoms in the conformer
+        - subset: np.ndarray of shape (1) containing "molecule3d"
+    """
     smiles = dm.to_smiles(mol, explicit_hs=False)
     # subset = dm.to_smiles(dm.to_scaffold_murcko(mol, make_generic=True), explicit_hs=False)
     x = get_atomic_number_and_charge(mol)
@@ -29,7 +49,8 @@ def read_mol(mol, energy):
     return res
 
 
-def _read_sdf(sdf_path, properties_path):
+def _read_sdf(sdf_path: str, properties_path: str) -> List[Dict[str, np.ndarray]]:
+    """Reads the sdf path and properties file."""
     properties = pd.read_csv(properties_path, dtype={"cid": str})
     properties.drop_duplicates(subset="cid", inplace=True, keep="first")
     xys = properties[["cid", "scf energy"]]
@@ -45,6 +66,22 @@ def _read_sdf(sdf_path, properties_path):
 
 
 class Molecule3D(BaseDataset):
+    """
+    Molecule3D dataset consists of 3,899,647 molecules with ground state geometries and energies
+    calculated at B3LYP/6-31G* level of theory. The molecules are extracted from the
+    PubChem database and cleaned by removing invalid molecule files.
+
+    Usage:
+    ```python
+    from openqdc.datasets import Molecule3D
+    dataset = Molecule3D()
+    ```
+
+    References:
+    - https://arxiv.org/abs/2110.01717
+    - https://github.com/divelab/MoleculeX
+    """
+
     __name__ = "molecule3d"
     __energy_methods__ = ["b3lyp_6-31g*"]
 
diff --git a/src/openqdc/datasets/orbnet_denali.py b/src/openqdc/datasets/orbnet_denali.py
index 452cce1..2d8b093 100644
--- a/src/openqdc/datasets/orbnet_denali.py
+++ b/src/openqdc/datasets/orbnet_denali.py
@@ -1,4 +1,5 @@
 from os.path import join as p_join
+from typing import Dict, List
 
 import datamol as dm
 import numpy as np
@@ -9,7 +10,7 @@
 from openqdc.utils.molecule import atom_table
 
 
-def read_mol(mol_id, conf_dict, base_path, energy_target_names):
+def read_mol(mol_id, conf_dict, base_path, energy_target_names: List[str]) -> Dict[str, np.ndarray]:
     res = []
     for conf_id, conf_label in conf_dict.items():
         try:
@@ -34,6 +35,23 @@ def read_mol(mol_id, conf_dict, base_path, energy_target_names):
 
 
 class OrbnetDenali(BaseDataset):
+    """
+    Orbnet Denali is a collection of 2.3 million conformers from 212,905 unique molecules. It performs
+    DFT (ωB97X-D3/def2-TZVP) calculations on molecules and geometries consisting of organic molecules
+    and chemistries, with protonation and tautomeric states, non-covalent interactions, common salts,
+    and counterions, spanning the most common elements in bio and organic chemistry.
+
+    Usage:
+    ```python
+    from openqdc.datasets import OrbnetDenali
+    dataset = OrbnetDenali()
+    ```
+
+    References:
+    - https://arxiv.org/pdf/2107.00299.pdf
+    - https://figshare.com/articles/dataset/OrbNet_Denali_Training_Data/14883867
+    """
+
     __name__ = "orbnet_denali"
     __energy_methods__ = ["wb97x-d3_tz", "gfn1_xtb"]
 
@@ -53,13 +71,6 @@ def read_raw_entries(self):
             for mol_id, group in df.groupby("mol_id")
         }
 
-        # print(df.head())
-        # tmp = df.to_dict('index')
-        # for i, k in enumerate(tmp):
-        #     print(k, tmp[k])
-        #     if i > 10:
-        #         break
-        # exit()
         fn = lambda x: read_mol(x[0], x[1], self.root, self.energy_target_names)
         res = dm.parallelized(fn, list(labels.items()), scheduler="threads", n_jobs=-1, progress=True)
         samples = sum(res, [])
diff --git a/src/openqdc/datasets/qmugs.py b/src/openqdc/datasets/qmugs.py
index b528f42..d15d83b 100644
--- a/src/openqdc/datasets/qmugs.py
+++ b/src/openqdc/datasets/qmugs.py
@@ -36,6 +36,22 @@ def read_mol(mol_dir):
 
 
 class QMugs(BaseDataset):
+    """
+    The QMugs dataset contains 2 million conformers for 665k biologically and pharmacologically relevant molecules
+    extracted from the ChEMBL database. The atomic and molecular properties are calculated using both,
+    semi-empirical methods (GFN2-xTB) and DFT method (ωB97X-D/def2-SVP).
+
+    Usage:
+    ```python
+    from openqdc.datasets import QMugs
+    dataset = QMugs()
+    ```
+
+    References:
+    - https://www.nature.com/articles/s41597-022-01390-7#ethics
+    - https://www.research-collection.ethz.ch/handle/20.500.11850/482129
+    """
+
     __name__ = "qmugs"
     __energy_methods__ = ["gfn2_xtb", "b3lyp/6-31g*"]