diff --git a/.env.sample b/.env.sample
index 9f45506..6cc9a18 100644
--- a/.env.sample
+++ b/.env.sample
@@ -14,3 +14,6 @@ AWS_REGION=
 
 # CDN for image uploads
 IMAGES_CDN_HOST=
+
+# Build notifications as part of CI
+SLACK_WEBHOOK_URL=
diff --git a/Dockerfile b/Dockerfile
index 7eaee2e..410bd67 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -40,6 +40,3 @@ RUN bundle install --jobs 20 --retry 5
 
 # Copy the main application.
 COPY . ./
-
-# Default command
-ENTRYPOINT ['/app/robles/bin/robles']
diff --git a/Gemfile b/Gemfile
index 3465ac4..0e83ad9 100644
--- a/Gemfile
+++ b/Gemfile
@@ -33,6 +33,9 @@ gem 'concurrent-ruby', '~> 1.1'
 # Interacting with github
 gem 'octokit', '~> 4.18'
 
+# Sending notifications to slack
+gem 'slack-notifier', '~> 2.3', '>= 2.3.2'
+
 group :development do
   # For integration with VSCode
   gem 'debase', '~> 0.2.4.1'
diff --git a/Gemfile.lock b/Gemfile.lock
index 9e1496f..eafef47 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -13,20 +13,20 @@ GEM
       public_suffix (>= 2.0.2, < 5.0)
     ast (2.4.0)
     aws-eventstream (1.1.0)
-    aws-partitions (1.313.0)
-    aws-sdk-core (3.95.0)
+    aws-partitions (1.325.0)
+    aws-sdk-core (3.97.1)
       aws-eventstream (~> 1, >= 1.0.2)
       aws-partitions (~> 1, >= 1.239.0)
       aws-sigv4 (~> 1.1)
       jmespath (~> 1.0)
-    aws-sdk-kms (1.31.0)
+    aws-sdk-kms (1.33.0)
       aws-sdk-core (~> 3, >= 3.71.0)
       aws-sigv4 (~> 1.1)
-    aws-sdk-s3 (1.64.0)
-      aws-sdk-core (~> 3, >= 3.83.0)
+    aws-sdk-s3 (1.67.1)
+      aws-sdk-core (~> 3, >= 3.96.1)
       aws-sdk-kms (~> 1)
       aws-sigv4 (~> 1.1)
-    aws-sigv4 (1.1.3)
+    aws-sigv4 (1.1.4)
       aws-eventstream (~> 1.0, >= 1.0.2)
     backport (1.1.2)
     benchmark (0.1.0)
@@ -40,7 +40,7 @@ GEM
       multipart-post (>= 1.2, < 3)
     git (1.7.0)
       rchardet (~> 1.8)
-    i18n (1.8.2)
+    i18n (1.8.3)
       concurrent-ruby (~> 1.0)
     jaro_winkler (1.5.4)
     jmespath (1.4.0)
@@ -55,31 +55,36 @@ GEM
       faraday (>= 0.9)
       sawyer (~> 0.8.0, >= 0.5.3)
     parallel (1.19.1)
-    parser (2.7.1.2)
+    parser (2.7.1.3)
       ast (~> 2.4.0)
     public_suffix (4.0.5)
     rainbow (3.0.0)
     rake (13.0.1)
     rchardet (1.8.0)
     redcarpet (3.5.0)
-    reverse_markdown (1.4.0)
+    regexp_parser (1.7.0)
+    reverse_markdown (2.0.0)
       nokogiri
     rexml (3.2.4)
-    rubocop (0.81.0)
-      jaro_winkler (~> 1.5.1)
+    rubocop (0.85.0)
       parallel (~> 1.10)
       parser (>= 2.7.0.1)
       rainbow (>= 2.2.2, < 4.0)
+      regexp_parser (>= 1.7)
       rexml
+      rubocop-ast (>= 0.0.3)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 1.4.0, < 2.0)
+    rubocop-ast (0.0.3)
+      parser (>= 2.7.0.1)
     ruby-debug-ide (0.7.2)
       rake (>= 0.8.1)
     ruby-progressbar (1.10.1)
     sawyer (0.8.2)
       addressable (>= 2.3.5)
       faraday (> 0.8, < 2.0)
-    solargraph (0.39.7)
+    slack-notifier (2.3.2)
+    solargraph (0.39.8)
       backport (~> 1.1)
       benchmark
       bundler (>= 1.17.2)
@@ -88,7 +93,7 @@ GEM
       maruku (~> 0.7, >= 0.7.3)
       nokogiri (~> 1.9, >= 1.9.1)
       parser (~> 2.3)
-      reverse_markdown (~> 1.0, >= 1.0.5)
+      reverse_markdown (>= 1.0.5, < 3)
       rubocop (~> 0.52)
       thor (~> 1.0)
       tilt (~> 2.0)
@@ -119,6 +124,7 @@ DEPENDENCIES
   redcarpet (~> 3.5)
   rubocop (~> 0.81)
   ruby-debug-ide (~> 0.7.2)
+  slack-notifier (~> 2.3, >= 2.3.2)
   solargraph (~> 0.39)
   thor (~> 1.0, >= 1.0.1)
   zeitwerk (~> 2.3)
diff --git a/app/commands/robles_cli.rb b/app/commands/robles_cli.rb
index fdf5bd3..b6893fd 100644
--- a/app/commands/robles_cli.rb
+++ b/app/commands/robles_cli.rb
@@ -2,6 +2,11 @@
 
 # Overall CLI app for robles
 class RoblesCli < Thor
+  # Ensures that invalid arguments etc result in a failure response to the shell
+  def self.exit_on_failure?
+    true
+  end
+
   desc 'render', 'renders book'
   option :'publish-file', type: :string, desc: 'Location of the publish.yaml file'
   option :local, type: :boolean
diff --git a/app/lib/api/alexandria/book_uploader.rb b/app/lib/api/alexandria/book_uploader.rb
index 6280c7a..8d6a3cc 100644
--- a/app/lib/api/alexandria/book_uploader.rb
+++ b/app/lib/api/alexandria/book_uploader.rb
@@ -41,6 +41,7 @@ def conn
           faraday.response(:logger, logger) do |logger|
             logger.filter(/(Token token=\\\")(\w+)/, '\1[REMOVED]')
           end
+          faraday.response(:raise_error)
           faraday.token_auth(ALEXANDRIA_SERVICE_API_TOKEN)
           faraday.adapter(Faraday.default_adapter)
         end
diff --git a/app/lib/renderer/image_attributes.rb b/app/lib/renderer/image_attributes.rb
index dc5add1..871255b 100644
--- a/app/lib/renderer/image_attributes.rb
+++ b/app/lib/renderer/image_attributes.rb
@@ -35,6 +35,7 @@ def width_class(alt_text)
       width_match = /width=(\d+)%/.match(alt_text)
       return if width_match.blank?
 
+      # Convert width request to a class that's a multiple of 10
       width = width_match[1].to_i.round(-1).clamp(0, 100)
       "l-image-#{width}"
     end
diff --git a/app/lib/runner/base.rb b/app/lib/runner/base.rb
index 34d8aee..5b8a3bd 100644
--- a/app/lib/runner/base.rb
+++ b/app/lib/runner/base.rb
@@ -4,6 +4,7 @@ module Runner
   # Base class with shared functionality
   class Base
     include Util::Logging
+    include Util::SlackNotifiable
 
     def self.runner
       return Runner::Ci.new if CI
@@ -23,16 +24,18 @@ def render(publish_file:, local: false)
       book
     end
 
-    def publish(publish_file:)
+    def publish(publish_file:) # rubocop:disable Metrics/MethodLength
       publish_file ||= default_publish_file
-
       parser = Parser::Publish.new(file: publish_file)
       book = parser.parse
       image_provider = ImageProvider::Provider.new(book: book)
       image_provider.process
-      renderer = Renderer::Book.new(book: book, image_provider: image_provider)
-      renderer.render
+      Renderer::Book.new(book: book, image_provider: image_provider).render
       Api::Alexandria::BookUploader.upload(book)
+      notify_success(book: book)
+    rescue StandardError => e
+      notify_failure(book: defined?(book) ? book : nil, details: e.full_message)
+      raise e
     end
 
     def lint(publish_file:, options: {})
diff --git a/app/lib/util/slack_notifiable.rb b/app/lib/util/slack_notifiable.rb
new file mode 100644
index 0000000..b372bce
--- /dev/null
+++ b/app/lib/util/slack_notifiable.rb
@@ -0,0 +1,119 @@
+# frozen_string_literal: true
+
+module Util
+  # Adds methods that allow slack notifications
+  module SlackNotifiable # rubocop:disable Metrics/ModuleLength
+    extend ActiveSupport::Concern
+
+    SUCCESS_IMAGE_URL = 'https://wolverine.raywenderlich.com/v3-resources/razebot/images/object_textkit-book.png'
+    FAILURE_IMAGE_URL = 'https://wolverine.raywenderlich.com/v3-resources/razebot/images/object_errors.png'
+    ROBLES_CONTEXT_IMAGE_URL = 'https://wolverine.raywenderlich.com/v3-resources/razebot/images/object_box-of-books.png'
+
+    def notify_success(book:)
+      return unless notifiable?
+
+      notifier.post(blocks: success_blocks(book: book))
+    end
+
+    def notify_failure(book:, details: nil)
+      return unless notifiable?
+
+      notifier.post(blocks: failure_blocks(book: book, details: details || 'N/A'))
+    end
+
+    def notifiable?
+      SLACK_WEBHOOK_URL.present?
+    end
+
+    def notifier
+      @notifier ||= Slack::Notifier.new(SLACK_WEBHOOK_URL, channel: SLACK_CHANNEL, username: SLACK_USERNAME)
+    end
+
+    def success_blocks(book:)
+      [
+        intro_section(book: book,
+                      message: ':white_check_mark: Book publication successful!',
+                      image_url: SUCCESS_IMAGE_URL,
+                      alt_text: 'Publication successful'),
+        {
+          type: 'divider'
+        },
+        context
+      ]
+    end
+
+    def failure_blocks(book:, details:) # rubocop:disable Metrics/MethodLength
+      [
+        intro_section(book: book,
+                      message: ':x: Book publication failed!',
+                      image_url: FAILURE_IMAGE_URL,
+                      alt_text: 'Publication failed'),
+        {
+          type: 'section',
+          text: {
+            type: 'mrkdwn',
+            text: "```#{details}```"
+          }
+        },
+        {
+          type: 'divider'
+        },
+        context
+      ]
+    end
+
+    def standard_fields(book:) # rubocop:disable Metrics/MethodLength
+      [
+        {
+          type: 'mrkdwn',
+          text: "*Book*\n#{book&.title || '_unknown_'}"
+        },
+        {
+          type: 'mrkdwn',
+          text: "*SKU*\n`#{book&.sku || 'unknown'}`"
+        },
+        {
+          type: 'mrkdwn',
+          text: "*Edition*\n#{book&.edition || '_unknown_'}"
+        },
+        {
+          type: 'mrkdwn',
+          text: "*Environment*\n`#{ENVIRONMENT}`"
+        }
+      ]
+    end
+
+    def intro_section(book:, message:, image_url:, alt_text:) # rubocop:disable Metrics/MethodLength
+      {
+        type: 'section',
+        text: {
+          type: 'mrkdwn',
+          text: message
+        },
+        fields: standard_fields(book: book),
+        accessory: {
+          type: 'image',
+          image_url: image_url,
+          alt_text: alt_text
+        }
+      }
+    end
+
+    def context # rubocop:disable Metrics/MethodLength
+      {
+        type: 'context',
+        elements: [
+          {
+            type: 'image',
+            image_url: ROBLES_CONTEXT_IMAGE_URL,
+            alt_text: 'robles via razebot'
+          },
+          {
+            type: 'mrkdwn',
+            text: 'This is a message sent from *robles* via *razebot*.'
+          }
+        ]
+      }
+    end
+  end
+end
diff --git a/config/initialisers/environment.rb b/config/initialisers/environment.rb
new file mode 100644
index 0000000..d4efdc2
--- /dev/null
+++ b/config/initialisers/environment.rb
@@ -0,0 +1,3 @@
+# frozen_string_literal: true
+
+ENVIRONMENT = ENV['ENV'] || 'development'
diff --git a/config/initialisers/slack.rb b/config/initialisers/slack.rb
new file mode 100644
index 0000000..11e8233
--- /dev/null
+++ b/config/initialisers/slack.rb
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+SLACK_WEBHOOK_URL = ENV['SLACK_WEBHOOK_URL']
+SLACK_CHANNEL = ENV['SLACK_CHANNEL'] || '#robles'
+SLACK_USERNAME = ENV['SLACK_USERNAME'] || 'razebot'