diff --git a/docs/DeveloperGuide.md b/docs/DeveloperGuide.md
index d27c8cadf9c..369739df506 100644
--- a/docs/DeveloperGuide.md
+++ b/docs/DeveloperGuide.md
@@ -119,17 +119,17 @@ How the parsing works:
 
 <img src="images/ModelClassDiagram.png" width="450" />
 
-
 The `Model` component,
 
-* stores the address book data i.e., all `Person` objects (which are contained in a `UniquePersonList` object).
-* stores the currently 'selected' `Person` objects (e.g., results of a search query) as a separate _filtered_ list which is exposed to outsiders as an unmodifiable `ObservableList<Person>` that can be 'observed' e.g. the UI can be bound to this list so that the UI automatically updates when the data in the list change.
+* stores the address book data i.e., all `Person` derivative objects (which are contained in a `UniquePersonList` object) and
+* all `Appointment` objects (which are contained in a `UniqueAppointmentList` object)
+* stores the currently 'selected' `Person` objects (e.g., results of a search query, either a `Patient` or `Doctor` instance) and `Appointment` object (e.g results of an query) as a separate _filtered_ list which is exposed to outsiders as an unmodifiable `ObservableList<Person>` and `ObservableList<Appointment>` that can be 'observed' e.g. the UI can be bound to this list so that the UI automatically updates when the data in the list change.
 * stores a `UserPref` object that represents the user’s preferences. This is exposed to the outside as a `ReadOnlyUserPref` objects.
 * does not depend on any of the other three components (as the `Model` represents data entities of the domain, they should make sense on their own without depending on other components)
 
-<div markdown="span" class="alert alert-info">:information_source: **Note:** An alternative (arguably, a more OOP) model is given below. It has a `Tag` list in the `AddressBook`, which `Person` references. This allows `AddressBook` to only require one `Tag` object per unique tag, instead of each `Person` needing their own `Tag` objects.<br>
+<div markdown="span" class="alert alert-info">:information_source: **Note:** For a clearer Class Diagram image, please refer to the handdrawn version below, it is exactly the same as the Class Diagram generated above, only drawn with straight lines for clarity and neatness.<br>
 
-<img src="images/BetterModelClassDiagram.png" width="450" />
+<img src="images/ModelClassDiagramHandDrawn.png" width="450" />
 
 </div>
 
diff --git a/docs/diagrams/ModelClassDiagram.puml b/docs/diagrams/ModelClassDiagram.puml
index 0de5673070d..ff937ab63c6 100644
--- a/docs/diagrams/ModelClassDiagram.puml
+++ b/docs/diagrams/ModelClassDiagram.puml
@@ -13,12 +13,23 @@ Class ModelManager
 Class UserPrefs
 
 Class UniquePersonList
-Class Person
-Class Address
-Class Email
+Class UniqueAppointmentList
+
+Class "{Abstract}\nPerson" as Person
+Class Patient
+Class Doctor
+
+Class Appointment
+Class AppointmentDate
+Class AppointmentID
+
+Class Type
+Class NRIC
 Class Name
+Class DoB
 Class Phone
-Class Tag
+
+Class "<<enumeration>>\nType\n\nPatient\nDoctor"
 
 Class I #FFFFFF
 }
@@ -36,19 +47,22 @@ ModelManager -right-> "1" UserPrefs
 UserPrefs .up.|> ReadOnlyUserPrefs
 
 AddressBook *--> "1" UniquePersonList
-UniquePersonList --> "~* all" Person
-Person *--> Name
-Person *--> Phone
-Person *--> Email
-Person *--> Address
-Person *--> "*" Tag
+AddressBook *--> "1" UniqueAppointmentList
+UniquePersonList ---> "~* all" Person
+UniqueAppointmentList -down--> "~* all" Appointment
+Person *---> Type
+Person *---> NRIC
+Person *---> Name
+Person *---> DoB
+Person *---> Phone
 
-Person -[hidden]up--> I
-UniquePersonList -[hidden]right-> I
+Doctor .right.|> Person
+Patient .--|> Person
 
-Name -[hidden]right-> Phone
-Phone -[hidden]right-> Address
-Address -[hidden]right-> Email
+Appointment *--> AppointmentDate
+Appointment *--> AppointmentID
+Appointment *--> "2(Patient & Doctor)" NRIC
 
 ModelManager --> "~* filtered" Person
+ModelManager --> "~* filtered" Appointment
 @enduml
diff --git a/docs/images/ModelClassDiagram.png b/docs/images/ModelClassDiagram.png
index a19fb1b4ac8..b6c5d6436d5 100644
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diff --git a/docs/images/ModelClassDiagramHandDrawn.png b/docs/images/ModelClassDiagramHandDrawn.png
new file mode 100644
index 00000000000..e3080c734a3
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