Staying motivated and productive is crucial for entrepreneurs--after all, rejection is pretty common in this line of work. Here are five newsletters to keep you on task and inspired during the good and bad times:

1. Perfect your perch

The Looking Glass by Julie Zhuo is a must for design mavens. She is a VP of design at Facebook and also maintains a popular design blog on Medium. As a product designer, Zhuo shares her insights into her work and life, such as why she chose design and what it feels like to be a working mother. In her newsletter, she answers a "question of the week" from her readers. A recent one was: "Have you ever managed a friend at work? If so, how did you navigate the decision?"

2. Juice your creativity

The Brain Pickings newsletter offers a selection of curated articles with topics "spanning art, science, psychology, design, philosophy, history, politics, anthropology." The weekly installments are the brainchild of Maria Popova, a Brooklyn-based writer and blogger. It started in 2006, inspired by her belief in the role of interdisciplinary knowledge in living wisely. Every Sunday, the newsletter features passages from novels, autobiographies, and other various types of literature.

3. Build your emotional intelligence

The Book of Life is a website and newsletter that Alain de Botton, TED speaker and author of the recent novel The Course of Love, sends out every Sunday. The newsletter presents ideas in five sections, dubbed "Capitalism," "Work," "Relationships," "Self," "Culture," and "Curriculum." It is a byproduct of an online platform for articles and videos devoted to emotional education for adults.

4. Boost your business IQ

Digital strategist Sarah Morgan's website and newsletter XO Sarah feature her tips for running an online business, such as how to share or grow a blog, strengthen social-media presence, and drive revenue online. In her newsletter, she talks about tools she uses to boost productivity and manage her blog for bloggers, freelancers, and business owners. You can sign up for the newsletter at the bottom of the site.

5. Get schooled

Tim Ferriss, the author of The 4-Hour Workweek, runs a business blog and podcast where he interviews guests from a diverse range of industries, including entrepreneurs. His past guests include well-known names like Arnold Schwarzenegger, Malcolm Gladwell, and Debbie Millman, who share their routines and tactics. In his newsletter, 5-Bullet Friday, he recommends a conglomerate of articles, brands, or songs that he has found interesting during the week.