diff --git a/data/stopwords.txt b/data/stopwords.txt
index 7336c7c..5b0a618 100644
--- a/data/stopwords.txt
+++ b/data/stopwords.txt
@@ -1 +1 @@
-a,able,about,across,after,all,almost,also,am,among,an,and,any,are,as,at,be,because,been,but,by,can,cannot,could,dear,did,do,does,either,else,ever,every,for,from,get,got,had,has,have,he,her,hers,him,his,how,however,i,if,in,into,is,it,its,just,least,let,like,likely,may,me,might,most,must,my,neither,no,nor,not,of,off,often,on,only,or,other,our,own,rather,said,say,says,she,should,since,so,some,than,that,the,their,them,then,there,these,they,this,tis,to,too,twas,us,wants,was,we,were,what,when,where,which,while,who,whom,why,will,with,would,yet,you,your,one,out,more,now,first,two,very,such,same,shall,upon,before,therefore,great,made,even,same,work,make,being,through,here,way,true,see,time,those,place,much,without,body,whole,another,thus,set,new,given,both,above,well,part,between,end,order,each,form,gutenberg
+a,able,about,across,after,all,almost,also,am,among,an,and,any,are,as,at,be,because,been,but,by,can,cannot,could,dear,did,do,does,either,else,ever,every,for,from,get,got,had,has,have,he,her,hers,him,his,how,however,i,if,in,into,is,it,its,just,least,let,like,likely,may,me,might,most,must,my,neither,no,nor,not,of,off,often,on,only,or,other,our,own,rather,said,say,says,she,should,since,so,some,than,that,the,their,them,then,there,these,they,this,tis,to,too,twas,us,wants,was,we,were,what,when,where,which,while,who,whom,why,will,with,would,yet,you,your,one,out,more,now,first,two,very,such,same,shall,upon,before,therefore,great,made,even,same,work,make,being,through,here,way,true,see,time,those,place,much,without,body,whole,another,thus,set,new,given,both,above,well,part,between,end,order,each,form,gutenberg,many
diff --git a/gutenberg.rb b/gutenberg.rb
index 84d20f6..f28f5d0 100644
--- a/gutenberg.rb
+++ b/gutenberg.rb
@@ -23,6 +23,6 @@ def run!(predictor_klass, opts={})
   puts "Accuracy: #{accuracy}"
 end
 
-run!(SimplePredictor)
+# run!(SimplePredictor)
 run!(ComplexPredictor, debug: true)
 
diff --git a/lib/complex_predictor.rb b/lib/complex_predictor.rb
index b8921f3..5113f93 100644
--- a/lib/complex_predictor.rb
+++ b/lib/complex_predictor.rb
@@ -1,4 +1,5 @@
 require_relative 'predictor'
+require 'pry-byebug'
 
 class ComplexPredictor < Predictor
   # Public: Trains the predictor on books in our dataset. This method is called
@@ -7,6 +8,29 @@ class ComplexPredictor < Predictor
   # Returns nothing.
   def train!
     @data = {}
+
+    @all_books.each do |category, books|
+      @data[category] = Hash.new(0)
+      books.each do |filename, tokens|
+        tokens.each do |token|
+          if good_token?(token)
+            @data[category][token] += 1
+          end
+        end
+      end
+      sorted = sort_words(@data, category)
+      top_words = get_top_words(sorted)
+      @data[category][:top_words] = top_words
+    end
+  end
+
+  def sort_words(data, category)
+    data[category].sort_by { |k,v| v }.reverse
+  end
+
+  def get_top_words(sorted)
+    top = sorted.take(900)
+    top.map! { |word, count| word }
   end
 
   # Public: Predicts category.
@@ -15,8 +39,10 @@ def train!
   #
   # Returns a category.
   def predict(tokens)
-    # Always predict astronomy, for now.
-    :astronomy
+    counts = Hash.new(0)
+    @data.each do |category, _|
+      counts[category] = (tokens & @data[category][:top_words]).length
+    end
+    counts.max_by { |k,v| v }.first
   end
-end
-
+end
\ No newline at end of file