diff --git a/.travis.yml b/.travis.yml
index de91d53a..18c41fcc 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -37,9 +37,6 @@ before_install:
 - travis_retry curl -L https://www.stackage.org/stack/linux-x86_64 | tar xz --wildcards --strip-components=1 -C ~/.local/bin '*/stack'
 # Install Pandoc
 - travis_retry curl -L https://github.com/jgm/pandoc/releases/download/2.9.2.1/pandoc-2.9.2.1-1-amd64.deb -o $HOME/pandoc.deb && sudo dpkg -i $HOME/pandoc.deb
-# Install Lua
-- travis_retry curl -L http://www.lua.org/ftp/lua-5.4.0.tar.gz | tar zx && cd lua-5.4.0 && make linux test && sudo make install
-- travis_retry curl -L https://luarocks.org/releases/luarocks-3.3.1.tar.gz | tar zx && cd luarocks-3.3.1 && ./configure && make && sudo make install
 # Download and install agda, agda-stdlib, and agda2html
 - make travis-setup
 
diff --git a/Makefile b/Makefile
index 9225729e..cd3d2542 100644
--- a/Makefile
+++ b/Makefile
@@ -3,22 +3,12 @@ AGDA_FILES := $(shell find . -type f -and \( -path '*/src/*' -or -path '*/course
 AGDAI_FILES := $(shell find . -type f -and \( -path '*/src/*' -or -path '*/courses/*' \) -and -name '*.agdai')
 MARKDOWN_FILES := $(subst courses/,out/,$(subst src/,out/,$(subst .lagda.md,.md,$(AGDA_FILES))))
 PLFA_DIR := $(shell dirname $(realpath $(lastword $(MAKEFILE_LIST))))
-
 RUBY := ruby
 GEM := $(RUBY) -S gem
 BUNDLE := $(RUBY) -S bundle
 JEKYLL := $(BUNDLE) exec jekyll
 HTML_PROOFER := $(BUNDLE) exec htmlproofer
-
 LUA_FILES := $(shell find . -type f -and -path '*/epub/*' -and -name '*.lua')
-LUA := lua
-LUAROCKS := luarocks --lua-version=$(LUA_VERSION)
-LUA_MODULES := lua_modules
-PANDOC := /usr/bin/pandoc
-
-ifneq ($(wildcard $(LUA_MODULES)),)
-	LUA_FLAGS += -l epub/set_paths
-endif
 
 ifeq ($(AGDA_STDLIB_VERSION),)
 AGDA_STDLIB_URL := https://agda.github.io/agda-stdlib/
@@ -67,7 +57,7 @@ out/epub/:
 	mkdir -p out/epub/
 
 out/epub/plfa.epub: out/epub/ | $(AGDA_FILES) $(LUA_FILES) epub/main.css out/epub/acknowledgements.md
-	$(PANDOC) --strip-comments \
+	pandoc --strip-comments \
 		--css=epub/main.css \
 		--epub-embed-font='assets/fonts/mononoki.woff' \
 		--epub-embed-font='assets/fonts/FreeMono.woff' \
@@ -84,7 +74,7 @@ out/epub/plfa.epub: out/epub/ | $(AGDA_FILES) $(LUA_FILES) epub/main.css out/epu
 		epub/index.md
 
 out/epub/acknowledgements.md: src/plfa/acknowledgements.md _config.yml
-	 $(LUA) $(LUA_FLAGS) epub/render-liquid-template.lua _config.yml $< $@
+	 $(RUBY) epub/render-liquid-template.rb _config.yml $< $@
 
 
 # Convert literal Agda to Markdown
@@ -171,10 +161,7 @@ travis-setup:\
 	$(HOME)/.local/bin/acknowledgements\
 	$(HOME)/agda-stdlib-$(AGDA_STDLIB_VERSION)/src\
 	$(HOME)/.agda/defaults\
-	$(HOME)/.agda/libraries\
-	$(LUA_MODULES)/share/lua/$(LUA_VERSION)/cjson\
-	$(LUA_MODULES)/share/lua/$(LUA_VERSION)/tinyyaml.lua\
-	$(LUA_MODULES)/share/lua/$(LUA_VERSION)/liquid.lua
+	$(HOME)/.agda/libraries
 
 .phony: travis-setup
 
@@ -249,22 +236,3 @@ travis-uninstall-acknowledgements:
 travis-reinstall-acknowledgements: travis-uninstall-acknowledgements travis-reinstall-acknowledgements
 
 .phony: travis-install-acknowledgements travis-uninstall-acknowledgements travis-reinstall-acknowledgements
-
-
-# Lua
-
-travis-install-lua:\
-	$(LUA_MODULES)/share/lua/$(LUA_VERSION)/cjson\
-	$(LUA_MODULES)/share/lua/$(LUA_VERSION)/tinyyaml.lua\
-	$(LUA_MODULES)/share/lua/$(LUA_VERSION)/liquid.lua
-
-$(LUA_MODULES)/share/lua/$(LUA_VERSION)/cjson:
-# Only this particular version works:
-# https://github.com/mpx/lua-cjson/issues/56:
-	$(LUAROCKS) install --tree=$(LUA_MODULES) lua-cjson 2.1.0-1
-
-$(LUA_MODULES)/share/lua/$(LUA_VERSION)/tinyyaml.lua:
-	$(LUAROCKS) install --tree=$(LUA_MODULES) lua-tinyyaml
-
-$(LUA_MODULES)/share/lua/$(LUA_VERSION)/liquid.lua:
-	$(LUAROCKS) install --tree=$(LUA_MODULES) liquid
diff --git a/epub/render-liquid-template.lua b/epub/render-liquid-template.lua
deleted file mode 100644
index 7305bea3..00000000
--- a/epub/render-liquid-template.lua
+++ /dev/null
@@ -1,52 +0,0 @@
-local yaml = require 'tinyyaml'
-local liquid = require 'liquid'
-
--- Given a file name, return its file descriptor.
--- Throws an error on failure.
-local function errOpen (fname, mode)
-    local fd = io.open(fname, mode)
-    if fd == nil then
-        error('could not open file: ' .. fname)
-    end
-    return fd
-end
-
--- Given a file name and some data, overwrite the file with the data.
--- Throws an error on failure.
-local function errWrite (fname, data)
-    local fd = errOpen(fname, 'w')
-    local status, errstr = fd:write(data)
-    if status == nil then
-        error(fname .. ': ' .. errstr)
-    end
-end
-
--- Given a file name, return that file's entire contents.
--- Throws an error on failure.
-local function errReadAll (fname)
-    local data = errOpen(fname, 'r'):read('a')
-    if data == nil then
-        error('could not read from open file: ' .. fname)
-    end
-    return data
-end
-
-
--- We must have exactly three arguments.
-if #arg ~= 3 then
-    print('usage: ' .. arg[0] .. ' [yaml_file] [markdown_in_file] [markdown_out_file]')
-    os.exit(1)
-end
-
--- 1. Read YAML metadata from file, which we nest under the key 'site'.
-local metadata = { ['site'] = yaml.parse(errReadAll(arg[1])) }
-
--- 2. Read markdown document from file.
-local document = errReadAll(arg[2])
-
--- 3. Render the markdown document with the YAML metadata as context.
-local template = liquid.Template:parse(document)
-local result = template:render(liquid.InterpreterContext:new(metadata))
-
--- 4. Write rendered document to output file.
-errWrite(arg[3], result)
\ No newline at end of file
diff --git a/epub/render-liquid-template.rb b/epub/render-liquid-template.rb
new file mode 100644
index 00000000..927b25b5
--- /dev/null
+++ b/epub/render-liquid-template.rb
@@ -0,0 +1,19 @@
+#!/usr/bin/env ruby
+require 'yaml'
+require 'liquid'
+
+unless ARGV.length == 3
+  abort "Usage: render-liquid-template.rb [yaml_file] [markdown_in_file] [markdown_out_file]"
+end
+
+yaml_file, markdown_file_in, markdown_file_out = ARGV
+
+[yaml_file, markdown_file_in].each do |file|
+  unless File.file? file
+    abort "File does not exist: '%s'" % [file]
+  end
+end
+
+metadata = { 'site' => (YAML.load (File.read yaml_file)) }
+template = Liquid::Template.parse (File.read markdown_file_in)
+File.write markdown_file_out, (template.render metadata)