diff --git a/lectures/_toc.yml b/lectures/_toc.yml
index 57f9a386..ae484a9b 100644
--- a/lectures/_toc.yml
+++ b/lectures/_toc.yml
@@ -5,33 +5,26 @@ parts:
   numbered: true
   chapters:
   - file: about
-- caption: Supply and Demand
-  numbered: true
-  chapters:
-  - file: intro_supply_demand
-  - file: supply_demand_multiple_goods
-  - file: supply_demand_heterogeneity
-  - file: input_output
-- caption: Data and Measurement
+- caption: Economic Data 
   numbered: true
   chapters:
   - file: long_run_growth
   - file: business_cycle
-  - file: inflation_unemployment
   - file: inequality
-  - file: heavy_tails
-- caption: Useful Tools
+- caption: Essential Tools
   numbered: true
   chapters:
-  - file: geom_series
-  - file: prob_dist
   - file: linear_equations
   - file: eigen_I
-- caption: Simulation
+  - file: intro_supply_demand
+  - file: geom_series
+- caption: Probability and Distributions
   numbered: true
   chapters:
+  - file: prob_dist
   - file: lln_clt
   - file: monte_carlo
+  - file: heavy_tails
   - file: schelling
 - caption: Dynamics
   numbered: true
@@ -43,14 +36,6 @@ parts:
   - file: markov_chains_I
   - file: markov_chains_II
   - file: commod_price
-- caption: Modeling in Higher Dimensions
-  numbered: true
-  chapters:
-  - file: eigen_II
-  - file: lake_model
-  - file: asset_pricing
-  - file: networks
-  - file: samuelson
 - caption: Optimization
   numbered: true
   chapters:
@@ -58,12 +43,19 @@ parts:
   - file: comparative_adv
   - file: nonlinear
   - file: short_path
+- caption: Modeling in Higher Dimensions
+  numbered: true
+  chapters:
+  - file: eigen_II
+  - file: input_output
+  - file: lake_model
+  - file: asset_pricing
+  - file: networks
 - caption: Markets and Competitive Equilibrium
   numbered: true
   chapters:
-  - file: markets_welfare
-  - file: risk
-  - file: uncertainty
+  - file: supply_demand_multiple_goods
+  - file: supply_demand_heterogeneity
 - caption: Estimation
   numbered: true
   chapters:
diff --git a/lectures/eigen_II.md b/lectures/eigen_II.md
index 66cd3e51..77ee1165 100644
--- a/lectures/eigen_II.md
+++ b/lectures/eigen_II.md
@@ -27,7 +27,7 @@ In addition to what's in Anaconda, this lecture will need the following librarie
 ```{code-cell} ipython3
 :tags: [hide-output]
 
-!pip install graphviz
+!pip install graphviz quantecon
 ```
 
 ```{admonition} graphviz
diff --git a/lectures/inflation_unemployment.md b/lectures/inflation_unemployment.md
deleted file mode 100644
index 7e81e561..00000000
--- a/lectures/inflation_unemployment.md
+++ /dev/null
@@ -1,14 +0,0 @@
----
-jupytext:
-  text_representation:
-    extension: .md
-    format_name: myst
-kernelspec:
-  display_name: Python 3
-  language: python
-  name: python3
----
-
-# Inflation and Unemployment
-
-To be completed.
\ No newline at end of file
diff --git a/lectures/markets_welfare.md b/lectures/markets_welfare.md
deleted file mode 100644
index 7887ae3d..00000000
--- a/lectures/markets_welfare.md
+++ /dev/null
@@ -1,14 +0,0 @@
----
-jupytext:
-  text_representation:
-    extension: .md
-    format_name: myst
-kernelspec:
-  display_name: Python 3
-  language: python
-  name: python3
----
-
-# Markets and Welfare
-
-To be completed.
\ No newline at end of file
diff --git a/lectures/risk.md b/lectures/risk.md
deleted file mode 100644
index 736df113..00000000
--- a/lectures/risk.md
+++ /dev/null
@@ -1,14 +0,0 @@
----
-jupytext:
-  text_representation:
-    extension: .md
-    format_name: myst
-kernelspec:
-  display_name: Python 3
-  language: python
-  name: python3
----
-
-# Risk
-
-To be completed.
\ No newline at end of file
diff --git a/lectures/samuelson.md b/lectures/samuelson.md
deleted file mode 100644
index 36b3aa07..00000000
--- a/lectures/samuelson.md
+++ /dev/null
@@ -1,14 +0,0 @@
----
-jupytext:
-  text_representation:
-    extension: .md
-    format_name: myst
-kernelspec:
-  display_name: Python 3
-  language: python
-  name: python3
----
-
-# Multiplier Accelerator Model
-
-To be completed.
\ No newline at end of file
diff --git a/lectures/uncertainty.md b/lectures/uncertainty.md
deleted file mode 100644
index 7df29dda..00000000
--- a/lectures/uncertainty.md
+++ /dev/null
@@ -1,14 +0,0 @@
----
-jupytext:
-  text_representation:
-    extension: .md
-    format_name: myst
-kernelspec:
-  display_name: Python 3
-  language: python
-  name: python3
----
-
-# Uncertainty
-
-To be completed.
\ No newline at end of file