Forget about HOW to write a screenplay, this is a very insightful - I'd say indispensable - nuts & bolts BUSINESS book for screenwriters, but not your usual advice - Lent goes into great detail on factors that may seem trivial, but can actually make or break your next project.
He covers everything from why/if/how you need to move to L.A., how to network effectively, how to get a meeting, to how to comport yourself in said meeting, follow ups, pitching techniques for phone and in person, how to effectively network, legal ramifications of your deals & actions & just plain how to handle yourself on a business level as an industry professional.
I've read my copy numerous times. Dog eared and highlighted throughout, it's one of my best reference guides.