Fundamentals of the Options Market, by Michale Williams is one of my favorite entry level books. It covers the basics quickly: what is a Call and what is a Put--Long, Short, ITM, ATM, and OTM. So, if you are reading this and have no clue what any of those things are, buy this book, it's a very good resource to have around, especially if you are wanting to get serious about options.
This book also delves into Synthetics in detail, and goes over the building blocks for them. Synthetics let you construct Profit and Loss profiles that are similar to each other, but may reduce risk, or less capital intensive. I'll deal with those more later.
The book outlines a huge number of options strategies for each particular market situation. Including some rather advanced strategies, such as back spreads and front spreads. It also covers market basics, and how exactly that little gnome changes those ticker numbers so fast.
Options Markets also introduces us to Position Trading, another important concept that I will address later. But, very quickly, position trading allows you to identify where your risk is coming from, and how to hedge against it. Beginners and intermediates, this is a good book, and a resource to hang on to.