diff --git a/src/main/scala/pbdirect/PBReader.scala b/src/main/scala/pbdirect/PBReader.scala
index 5a9fca8..6d64fd9 100644
--- a/src/main/scala/pbdirect/PBReader.scala
+++ b/src/main/scala/pbdirect/PBReader.scala
@@ -81,6 +81,14 @@ object PBReader extends PBReaderImplicits {
   implicit object BooleanReader$ extends PBReader[Boolean] {
     override def read(input: CodedInputStream): Boolean = input.readBool()
   }
+  // Stored as variants, but larger in memory: https://groups.google.com/forum/#!topic/protobuf/Er39mNGnRWU
+  implicit object ByteReader$ extends PBReader[Byte] {
+    override def read(input: CodedInputStream): Byte = input.readInt32().toByte
+  }
+  // Stored as variants, but larger in memory: https://groups.google.com/forum/#!topic/protobuf/Er39mNGnRWU
+  implicit object ShortReader$ extends PBReader[Short] {
+    override def read(input: CodedInputStream): Short = input.readInt32().toShort
+  }
   implicit object IntReader$ extends PBReader[Int] {
     override def read(input: CodedInputStream): Int = input.readInt32()
   }
@@ -180,6 +188,14 @@ trait PBParserImplicits extends LowPriorityPBParserImplicits {
     instance { (index: Int, bytes: Array[Byte]) =>
       parser.parse(index, bytes).toMap
     }
+  implicit def collectionMapParser[K, V](implicit parser: PBParser[List[(K, V)]]): PBParser[collection.Map[K, V]] =
+    instance { (index: Int, bytes: Array[Byte]) =>
+      parser.parse(index, bytes).toMap
+    }
+  implicit def seqParser[A](implicit parser: PBParser[List[A]]): PBParser[Seq[A]] =
+    instance { (index: Int, bytes: Array[Byte]) =>
+      parser.parse(index, bytes)
+    }
 }
 
 object PBParser extends PBParserImplicits
diff --git a/src/main/scala/pbdirect/PBWriter.scala b/src/main/scala/pbdirect/PBWriter.scala
index d0bd930..9cd9f51 100644
--- a/src/main/scala/pbdirect/PBWriter.scala
+++ b/src/main/scala/pbdirect/PBWriter.scala
@@ -83,6 +83,14 @@ trait PBWriterImplicits extends LowPriorityPBWriterImplicits {
     override def writeTo(index: Int, value: Boolean, out: CodedOutputStream): Unit =
       out.writeBool(index, value)
   }
+  implicit object ByteWriter extends PBWriter[Byte] {
+    override def writeTo(index: Int, value: Byte, out: CodedOutputStream): Unit =
+      out.writeInt32(index, value)
+  }
+  implicit object ShortWriter extends PBWriter[Short] {
+    override def writeTo(index: Int, value: Short, out: CodedOutputStream): Unit =
+      out.writeInt32(index, value)
+  }
   implicit object IntWriter extends PBWriter[Int] {
     override def writeTo(index: Int, value: Int, out: CodedOutputStream): Unit =
       out.writeInt32(index, value)
@@ -120,6 +128,14 @@ trait PBWriterImplicits extends LowPriorityPBWriterImplicits {
     instance { (index: Int, value: Map[K, V], out: CodedOutputStream) =>
       writer.writeTo(index, value.toList, out)
     }
+  implicit def collectionMapWriter[K, V](implicit writer: PBWriter[List[(K, V)]]): PBWriter[collection.Map[K, V]] =
+    instance { (index: Int, value: collection.Map[K, V], out: CodedOutputStream) =>
+      writer.writeTo(index, value.toList, out)
+    }
+  implicit def seqWriter[A](implicit writer: PBWriter[List[A]]): PBWriter[Seq[A]] =
+    instance { (index: Int, value: Seq[A], out: CodedOutputStream) =>
+      writer.writeTo(index, value.toList, out)
+    }
   implicit def enumWriter[E](implicit values: Enum.Values[E], ordering: Ordering[E]): PBWriter[E] =
     instance { (index: Int, value: E, out: CodedOutputStream) =>
       out.writeInt32(index, Enum.toInt(value))
diff --git a/src/test/scala/pbdirect/PBReaderSpec.scala b/src/test/scala/pbdirect/PBReaderSpec.scala
index f97cde8..5655ac1 100644
--- a/src/test/scala/pbdirect/PBReaderSpec.scala
+++ b/src/test/scala/pbdirect/PBReaderSpec.scala
@@ -30,6 +30,16 @@ class PBReaderSpec extends WordSpecLike with Matchers {
       val bytes = Array[Byte](8, 1)
       bytes.pbTo[BooleanMessage] shouldBe BooleanMessage(Some(true))
     }
+    "read a Byte from Protobuf" in {
+      case class ByteMessage(value: Option[Byte])
+      val bytes = Array[Byte](8, 32)
+      bytes.pbTo[ByteMessage] shouldBe ByteMessage(Some(32))
+    }
+    "read a Short from Protobuf" in {
+      case class ShortMessage(value: Option[Short])
+      val bytes = Array[Byte](8, -1, 63)
+      bytes.pbTo[ShortMessage] shouldBe ShortMessage(Some(8191))
+    }
     "read an Int from Protobuf" in {
       case class IntMessage(value: Option[Int])
       val bytes = Array[Byte](8, 5)
@@ -105,11 +115,21 @@ class PBReaderSpec extends WordSpecLike with Matchers {
       val bytes = Array[Byte](8, 1, 8, 2, 8, 3, 8, 4)
       bytes.pbTo[RepeatedMessage] shouldBe RepeatedMessage(1 :: 2 :: 3 :: 4 :: Nil)
     }
+    "read a message with Seq from Protobuf" in {
+      case class RepeatedMessage(values: Seq[Int])
+      val bytes = Array[Byte](8, 1, 8, 2, 8, 3, 8, 4)
+      bytes.pbTo[RepeatedMessage] shouldBe RepeatedMessage(Seq(1, 2, 3, 4))
+    }
     "read a Map from Protobuf" in {
       case class MapMessage(values: Map[Int, String])
       val bytes = Array[Byte](10, 7, 8, 1, 18, 3, 111, 110, 101, 10, 7, 8, 2, 18, 3, 116, 119, 111)
       bytes.pbTo[MapMessage] shouldBe MapMessage(Map(1 -> "one", 2 -> "two"))
     }
+    "read a scala.collection.Map from Protobuf" in {
+      case class MapMessage(values: collection.Map[Int, String])
+      val bytes = Array[Byte](10, 7, 8, 1, 18, 3, 111, 110, 101, 10, 7, 8, 2, 18, 3, 116, 119, 111)
+      bytes.pbTo[MapMessage] shouldBe MapMessage(collection.Map(1 -> "one", 2 -> "two"))
+    }
     "read a nested message from Protobuf" in {
       case class InnerMessage(value: Option[Int])
       case class OuterMessage(text: Option[String], inner: Option[InnerMessage])
diff --git a/src/test/scala/pbdirect/PBWriterSpec.scala b/src/test/scala/pbdirect/PBWriterSpec.scala
index caf39a1..992fb02 100644
--- a/src/test/scala/pbdirect/PBWriterSpec.scala
+++ b/src/test/scala/pbdirect/PBWriterSpec.scala
@@ -32,6 +32,16 @@ class PBWriterSpec extends WordSpecLike with Matchers {
       val message = BooleanMessage(Some(true))
       message.toPB shouldBe Array[Byte](8, 1)
     }
+    "write a Byte to Protobuf" in {
+      case class ByteMessage(value: Option[Byte])
+      val message = ByteMessage(Some(32))
+      message.toPB shouldBe Array[Byte](8, 32)
+    }
+    "write a Short to Protobuf" in {
+      case class ShortMessage(value: Option[Short])
+      val message = ShortMessage(Some(8191))
+      message.toPB shouldBe Array[Byte](8, -1, 63)
+    }
     "write an Int to Protobuf" in {
       case class IntMessage(value: Option[Int])
       val message = IntMessage(Some(5))
@@ -105,12 +115,22 @@ class PBWriterSpec extends WordSpecLike with Matchers {
       val message = RepeatedMessage(1 :: 2 :: 3 :: 4 :: Nil)
       message.toPB shouldBe Array[Byte](8, 1, 8, 2, 8, 3, 8, 4)
     }
+    "write a message with Seq to Protobuf" in {
+      case class RepeatedMessage(values: Seq[Int])
+      val message = RepeatedMessage(Seq(1, 2, 3, 4))
+      message.toPB shouldBe Array[Byte](8, 1, 8, 2, 8, 3, 8, 4)
+    }
     "write a Map to Protobuf" in {
       case class MapMessage(values: Map[Int, String])
       val message = MapMessage(Map(1 -> "one", 2 -> "two"))
       message.toPB shouldBe Array[Byte](10, 7, 8, 1, 18, 3, 111, 110, 101, 10, 7, 8, 2, 18, 3, 116,
         119, 111)
     }
+    "write a scala.collection.Map to Protobuf" in {
+      case class MapMessage(values: collection.Map[Int, String])
+      val message = MapMessage(collection.Map(1 -> "one", 2 -> "two"))
+      message.toPB shouldBe Array[Byte](10, 7, 8, 1, 18, 3, 111, 110, 101, 10, 7, 8, 2, 18, 3, 116, 119, 111)
+    }
     "write a nested message to Protobuf" in {
       case class InnerMessage(value: Option[Int])
       case class OuterMessage(text: Option[String], inner: Option[InnerMessage])