diff --git a/Makefile b/Makefile
index 729acd4..bb318f5 100644
--- a/Makefile
+++ b/Makefile
@@ -15,17 +15,23 @@ ASCIIDOC_FLAGS = \
 
 all: $(PDF_PATH) $(EPUB_PATH)
 
-$(PDF_PATH): $(ASCIIDOC_FILES) $(FIGURES) Makefile metadata.yaml | output
+$(PDF_PATH): book.adoc $(ASCIIDOC_FILES) $(FIGURES) Makefile metadata.yaml | output
 	asciidoctor-pdf book.adoc $(ASCIIDOC_FLAGS) \
 		-o $@ \
 		-r asciidoctor-diagram \
-		-r asciidoctor-mathematical
+		-r asciidoctor-mathematical \
+		-r asciidoctor-kroki \
+		-a allow-uri-read \
+		--safe-mode server
 
-$(EPUB_PATH): $(ASCIIDOC_FILES) $(FIGURES) Makefile metadata.yaml | output
+$(EPUB_PATH): book.adoc $(ASCIIDOC_FILES) $(FIGURES) Makefile metadata.yaml | output
 	asciidoctor-epub3 book.adoc $(ASCIIDOC_FLAGS) \
 		-o $@ \
 		-r asciidoctor-diagram \
-		-r asciidoctor-mathematical
+		-r asciidoctor-mathematical \
+		-r asciidoctor-kroki \
+		-a allow-uri-read \
+		--safe-mode server
 
 count:
 	wc -w source/*
diff --git a/book.adoc b/book.adoc
index 8f0fd91..9c23bd4 100644
--- a/book.adoc
+++ b/book.adoc
@@ -11,6 +11,9 @@ Alexandra Thompson <name.lastname@foo.bar>
 :front-image: backgrounds/cover.png
 :back-image: backgrounds/back-cover.png
 :imagesdir: figures
+:kroki-server-url: https://kroki.io
+:kroki-fetch-diagram:
+:kroki-data-uri:
 
 include::source/front_matter.adoc[]