Bill Pugliano / Getty A new book about Elon Musk, written by Bloomberg technology reporter Ashlee Vance, is filled with quotes and anecdotes that provide an inside look at the entrepreneur behind Tesla Motors, SpaceX, and PayPal.

Several quotes paint a picture of just how much time Musk commits to the job. One person who previously worked with Musk even said Musk worked 23 hours a day, according to the book, "Elon Musk: Tesla, SpaceX, and the Quest for a Fantastic Future."

Musk even scolded a Tesla employee who missed an event to witness the birth of his child, Vance's book says.

Here's the email Musk reportedly sent to a Tesla employee who wasn't identified by name in the book:

That is no excuse. I am extremely disappointed. You need to figure out where your priorities are. We're changing the world and changing history, and you either commit or you don’t.

Musk took to Twitter on Monday to deny these comments, wiring that the email was "total BS & hurtful."

It is total BS & hurtful to claim that I told a guy to miss his child's birth just to attend a company meeting. I would never do that. — Elon Musk (@elonmusk) May 12, 2015

@voxdotcom I have never written or said this. Ashlee's book was not independently fact-checked. Should be taken w a grain of salt. — Elon Musk (@elonmusk) May 12, 2015

The Washington Post rounded up 22 of the most memorable quotes from Vance's new book about Musk. But, according to Musk, two of the quotes (including the one excerpted above) aren't accurate.

Of 22 Quotes from http://t.co/VA2KQ03NNR, 2 need correcting: 1. I strongly support pregnancy leave 2. I've never called myself a samurai — Elon Musk (@elonmusk) May 12, 2015

Tesla didn't provide any comment regarding the email cited in Vance's book.

The book appears to be filled with quotes that illustrate how Musk prioritizes his work.

When an employee complained in Tesla's early days about working too much, Musk said he would "tell those people they will get to see their families a lot when we go bankrupt," Ryan Popple, one of Tesla's earliest employees and now CEO of the electric-vehicle manufacturer Proterra, told Vance for the book.

You can read more about some of the most interesting things Musk said in Vance's new book over at The Washington Post.

(Note: This post has been updated on Tuesday, May 12 to include tweets from Elon Musk.)