diff --git a/docs/source/design/concepts/index.rst b/docs/source/design/concepts/index.rst
new file mode 100644
index 00000000..39250555
--- /dev/null
+++ b/docs/source/design/concepts/index.rst
@@ -0,0 +1,16 @@
+.. _about_concepts:
+
+==============
+Concept Schema
+==============
+
+A key part of the ingest library is the intermediate model of the
+"concept schema". This concept schema is a representation of the data that is
+being ingested, and is used to generate the final schema that is used to create
+the tables in the target api. 
+
+
+.. toctree::
+    :maxdepth: 2
+
+    samples_and_specimens.rst
diff --git a/docs/source/design/concepts/samples_and_specimens.rst b/docs/source/design/concepts/samples_and_specimens.rst
new file mode 100644
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+++ b/docs/source/design/concepts/samples_and_specimens.rst
@@ -0,0 +1,30 @@
+=====================
+Samples and Biospecimens
+=====================
+
+Although similarly named, samples and biospecimens refer to different things:
+
+- A **sample** is a physical piece of tissue, blood, or other material taken
+from a patient.
+- A **biospecimen** is a part of that sample, e.g. an aliquot of a sample. 
+
+While samples and biospecimens are distinct concepts, they share much in common.
+In fact, when the ingest library was first written, its primary target API, 
+the Kids First Data Service, only had a table for biospecimens. As a result,
+the ingest library's architecture provides for a biospecimen to share *all* the
+qualities of a sample. In fact, biospecimen is a child class of sample!
+
+This architecture allows the ingest library to be used against target APIs that,
+like the older versions of the Kids First Data Service, only have a table for
+biospecimens. 
+
+A sample has qualities:
+
+* A sample may have ino
+
+A biospecimen takes on 
+This
+is the smallest unit that a piece of biological material can take, as
+represented in the ingest library.
+
+Some 
\ No newline at end of file
diff --git a/docs/source/design/overview.rst b/docs/source/design/overview.rst
index d3cc1536..2cbd4e13 100644
--- a/docs/source/design/overview.rst
+++ b/docs/source/design/overview.rst
@@ -40,6 +40,7 @@ described.
    :maxdepth: 1
 
    value_principles
+   concepts/index.rst
    extract_mapping
    transform
    load