--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/java/fj/data/Reader.java	Fri Mar 20 21:04:03 2015 +0900
@@ -0,0 +1,50 @@
+package fj.data;
+
+import fj.F;
+import fj.F1Functions;
+
+/**
+ * The Reader monad (also called the function monad, so equivalent to the idea of F).
+ * Created by MarkPerry on 7/07/2014.
+ */
+public class Reader<A, B> {
+
+	private F<A, B> function;
+
+	public Reader(F<A, B> f) {
+		function = f;
+	}
+
+	public F<A, B> getFunction() {
+		return function;
+	}
+
+	public static <A, B> Reader<A, B> unit(F<A, B> f) {
+		return new Reader<A, B>(f);
+	}
+
+	public static <A, B> Reader<A, B> constant(B b) {
+		return unit(a -> b);
+	}
+
+	public B f(A a) {
+		return function.f(a);
+	}
+
+	public <C> Reader<A, C> map(F<B, C> f) {
+		return unit(F1Functions.andThen(function, f));
+	}
+
+	public <C> Reader<A, C> andThen(F<B, C> f) {
+		return map(f);
+	}
+
+	public <C> Reader<A, C> flatMap(F<B, Reader<A, C>> f) {
+		return unit(a -> f.f(function.f(a)).f(a));
+	}
+
+	public <C> Reader<A, C> bind(F<B, Reader<A, C>> f) {
+		return flatMap(f);
+	}
+
+}