Online courses or immersion experiences can take a $10 book and multiply its revenue-generating power by 10 or 20 fold. If you have written a professional or personal development book, your outline and sections of your book can transfer seamlessly over to a learning management system (LMS). According to Reuters, the eLearning market has accounted for $165.21 billion in revenue in 2017 and is expected to reach $275.10 billion by 2022.