When the beach chair beckons, you don’t want to be caught unprepared. I am not talking about having enough sunscreen, but rather having the right books to fill your beach bag.

This is the time of year to gather your favorite titles and indulge.

As a psychologist, people always ask me why we feel so much more emotionally free to indulge, to focus on pleasure during the summer months. There are a number of reasons:

Sunlight really boosts your spirits: The longer days offer more access to lengthy periods of sunlight. When your body absorbs UV light, it produces serotonin, a chemical in the brain that elevates your mood.

It can make you feel more energized and optimistic. We also know that sunlight also shuts down melatonin production, a hormone that can leave you feeling lethargic.

Childhood conditioning: Between the ages of six and 17, and sometimes longer, we have become conditioned to think about summer as a reliable break from routine, rules, and responsibility.

This mindset stays with us even though we are no longer on an academic calendar. While intellectually we recognize that adult responsibilities are year-round, we reflexively return to this childhood mindset in summer months.

Increased opportunities: During summer there are several holidays that allow us to indulge in increased social and physical activity, and some of us also enjoy even longer breaks. A significant effect of engaging in physical activity includes an increase in heart rate and the production of mood enhancing endorphins.

Additionally, summer vacations often involve extended time outdoors. Researchers have observed that with increased time spent in nature, we feel more relaxed and less anxious.

Opportunity for self-actualization: Psychologists have long recognized that people have an inherent drive towards self-actualization. Simply put, there is an inherent desire to fulfill our individual potential.

Not expressing our innate gifts can leave us anxious and depressed. Fortunately, in summer there is clearly more time and freedom to explore our talents and reexamine what gives us pleasure and purpose in both career and play.

When beach chairs and front porches call to you this summer – and your choice of indulgence is to read – here are three picks that will offer a satisfying and well-deserved escape. The following books are not typical light beach fare, but rather, chock full of intrigue, drama, and psychological depth.

Pam Jenoff’s “The Orphan’s Tale” is a riveting and poignant story of courage, loyalty and survival set in World War II. This well-researched and richly detailed story focuses on an extraordinary friendship forged between two women at the height of Nazi atrocity.

Having been cast out in disgrace after becoming pregnant by a Nazi officer, 16-year-old Noa finds herself alone and still grieving the child she was forced to give up at birth. While working in a railway station Noa discovers a train car filled with babies destined for a concentration camp. Noa makes a fateful decision that will change her life forever.

Desperate and struggling to survive while on the run, Noa is mercifully rescued by a traveling circus. For her safety and that of the small circus, Noa must learn to perform on a trapeze alongside the show’s star aerialist, Astrid.

Yet, Astrid is a woman with powerful secrets of her own. While jealousy, resentment and distrust threaten their relationship, Noa and Astrid quickly realize that they must help each other as true danger awaits them with each circus stop. But will their friendship be enough to protect them and those they come to love?

“Glory Over Everything” by Kathleen Grissom is historical fiction at its best. Well researched, rich in detail, and deeply moving, this is a story about courage and resilience in the face of bigotry and oppression.

It is 1830, and while young Jamie Pyke is passing as a white aristocrat amidst fashionable Philadelphia society, he is in fact, a runaway slave. In spite of well-learned social graces, he lives in constant fear of discovery, not only by those who have come to love him, but also by slave hunters who still seek to harm him.

Despite great vigilance, Jamie’s carefully constructed world begins to crumble around him when his beloved young black servant Pan is kidnapped and sold into slavery in North Carolina.

With no choice but to attempt to save the child he has sworn to protect, Jamie risks his life to return to the South. With great relief, Pyke finds that young Pan has been sheltered by Sukey, a fearless female slave on a North Carolina plantation, who has plans to get the boy out on the Underground Railroad.

Now all three will risk the perilous journey for freedom through both the Virginia backwoods and the dangerous Great Dismal Swamp. In the end, who will survive this terrifying run to safety and at what cost?

Cynthia Swanson’s “The Bookseller: A Novel,” is a poignant, thought provoking and highly evocative story of one woman’s deeply personal struggle to make sense of her life in the early 1960s.

It is 1962 and Denver native Kitty Miller is quite proud of her somewhat unconventional, single life as a 30-something bookshop owner. She loves the freedom, wonderful conversations and strong friendship she shares with her co-owner, and lifelong best friend, Frieda Green.

While early on there was also a relationship with a doctor named Kevin, it never quite worked out. Yet, Kitty enjoys her daily existence, free of any encumbrances and answering to no one. But one night, she begins to have strange dreams of an alternate life that suddenly seem all too real.

And with these dreams, come serious questions.

In her nightly dreams, it is 1963 and Kitty has a wholly different identity. She is a mother of three, living in an elegant Denver suburb with her adoring husband. While not entirely perfect, this life holds all the right ingredients. Indeed, at one time, it is the life that Kitty always imagined she’d ultimately have.

And with each vivid nightly foray into married life and the marital bed, the boundary between what is dream and what is reality becomes blurred.

As Kitty seems to be losing control and struggling to decide which life is really hers, we are all left breathless and guessing to the end – does this woman simply have an overactive imagination or is she bordering on delusional, or is there something else happening altogether?

Nancy Harris of Scituate is a licensed psychologist and a former instructor of psychology at Harvard Medical School.