diff --git a/README.md b/README.md
index e25631872818474101cd511cbe7ca4e2971e98f1..a3ea44ebbbeb1321afcb47accf8836c9ee7829a4 100644
--- a/README.md
+++ b/README.md
@@ -1 +1 @@
-# ICARTT reader
+# ICARTT file format reader and writer
diff --git a/icartt/dataset.py b/icartt/dataset.py
index 3d64ad6ac539ce23be97295b460218683cd987c8..c13dfab9ed5cc3c49374de6b758c90503a19d560 100644
--- a/icartt/dataset.py
+++ b/icartt/dataset.py
@@ -7,12 +7,16 @@ class Variable:
     '''
     @property
     def desc(self):
+        '''
+        Return variable description string as it appears in an ICARTT file
+        '''
         return self.splitChar.join( [self.name, self.units, self.units ] )
     def __init__(self, name, units, scale=1.0, miss=-9999999):
         self.name = name
         self.units = units
         self.scale = scale
         self.miss = str(miss)
+        self.splitChar    = ','
 
 class Dataset:
     '''
@@ -114,17 +118,22 @@ class Dataset:
         nul = [ prnt(self.splitChar.join( [ str(y) for y in x ] )) for x in self.data ]
 
     def make_filename(self):
+        '''
+        Create ICARTT-compliant file name based on the information contained in the dataset
+        '''
         return self.dataID + "_" +self.locationID + "_" +datetime.datetime.strftime(self.dateValid, '%Y%m%d') + "_" +"R" + self.revision + ".ict"
 
     # sanitize function
     def __readline(self, do_split=True):
         dmp = self.input_fhandle.readline().replace('\n', '').replace('\r','')
         if do_split:
-            dmp = [word.strip(' ') for word in dmp.split(self.splitChar)]
+            dmp = [word.strip(' ') for word in dmp.split(self.splitChar) ]
         return dmp
 
     def read_header(self):
-
+        '''
+        Read the ICARTT header (from file)
+        '''
         if self.input_fhandle.closed:
             self.input_fhandle = open(self.input_fhandle.name)
 
@@ -248,7 +257,9 @@ class Dataset:
         return [ float(x.replace(self.VAR[i].miss, 'NaN')) for i, x in enumerate(raw) ]
 
     def read_data(self):
-
+        '''
+        Read ICARTT data (from file)
+        '''
         if self.input_fhandle.closed:
             self.input_fhandle = open(self.input_fhandle.name)
 
@@ -259,7 +270,10 @@ class Dataset:
         self.input_fhandle.close()
 
     def read_first_and_last(self):
-
+        '''
+        Read first and last ICARTT data line (from file). Useful for quick estimates e.g. of the time extent
+        of big ICARTT files, without having to read the whole thing, which would be slow.
+        '''
         if self.input_fhandle.closed:
             self.input_fhandle = open(self.input_fhandle.name)