If you need a book, buy it. Just make sure you pay tax on the item. Then expense it. Digital too - read wherever's comfortable for you.
If you're interested in taking a course at an online academy like Unacdemy, Udemy, and Codeacy which will further your professional skills, get permission from your manager. Under most circumstances with prior approval, we'll reimburse you for the cost of the course, all registration fees, books, and course materials.