Yes, I have read many books on the topic and the three below stand out 

• Testosterone for Life: Recharge Your Vitality, Sex Drive, Muscle Mass, and Overall Health by Abraham Morgentaler, M.D.
• The Testosterone Syndrome: The Critical Factor for Energy, Health, and Sexuality-Reversing the Male Menopause by Eugene Shippen, M.D.. and William Fryer 
• Testosterone the therapy for real gentlemen by Thierry Hertoghe, M.D.

Dr. Hertoghe’s book is definitely the most current as well as comprehensive of the three with over five hundred pages of detailed information on the benefits of testosterone therapy for a multitude of conditions. However, it is more of a textbook for doctors to understand the merits of testosterone therapy for a variety of purposes. In addition, it costs around $300.00 so definitely not for someone who has a casual interest in the topic. Nevertheless, it’s stacked with incredible information and I am currently working my way through it. 

Here are some examples from the book regarding the benefits of optimal testosterone levels that you may not be aware of. 

• Testosterone levels are well known to improve mood, recall, memory, creativity, courage, problem-solving, focus, confidence, energy, and determination. What many aren’t aware of is optimal testosterone levels can also improve compassion. This is not too surprising as when you feel genuinely better about yourself and are full of vitality you’re more likely to be concerned about the well being of others and are more inclined to want to make a difference. 
• Testosterone increases energy by improving mitochondria the energy producers in cells. Both men and women with depleted testosterone levels often report being very fatigued and low on motivation. Not just motivation for sex but low on motivation and drive categorically. When your testosterone levels are at a healthy level you’re much more likely to feel energetic and tenacious ready to take charge of problems and smash obstacles. 
• Testosterone improves hair growth and thickness. Many believe testosterone plays a big role in hair loss but it is only the case if there is excessive conversion to DHT Some conversion to DHT is important as many of the benefits that are often associated with testosterone such as an increase in sex drive and function are more due to DHT. Men prone to baldness can have a high conversion of testosterone to DHT but also a genetic proclivity for DHT having an affinity for hair follicles on the scalp. Dr. Hertoghe used testosterone therapy with finasteride to help regrow his hair which started to become very apparent after a year of continued use. He doesn’t recommend finasteride alone as it can lower DHT too much and DHT is crucial for sex drive and function. If you are going to take finasteride he recommends taking testosterone as well to ensure testosterone levels are high while the ideal dosage of finasteride keeps DHT at the same level or reduces excessive amounts. 
• Testosterone makes men calmer and reduces anxiety. It increases courage and drive so you’re better equipped to handle whatever life throws your way and focus on facing adversity head-on. Anxiety and the inability to remain calm often come from a feeling of being overwhelmed. If you have more determination and drive you’re less likely to be anxious. Those who are not in the know often associate testosterone with violent behavior which is not only erroneous but an oversimplification as a proclivity for violent behavior is more complex than simply one’s testosterone level. In my experience, I feel far more confident and driven when my testosterone levels are ideal and this, in turn, makes me feel calmer as well
• Testosterone reduces depression. With depleted testosterone levels there are often low levels of estrogen as well and optimal estrogen levels are crucial for mood as well as sex drive and function. According to Dr. Hertoghe, catecholestrogens which are created from estrogens are natural anti-depressants and help perk up the brain. 

Estrogen is made from testosterone in both men and women. Women, of course, have a much higher conversion resulting in much lower levels of testosterone than men and much higher levels of estrogen than men (although estrogen dominance is on the rise big time in men and many have levels close to what women have which is all too apparent in how they store excess body fat). If men don’t produce enough testosterone they will not, in turn, produce enough estrogen and men need a healthy balance of both. Of course, men can have much-reduced testosterone due to too much conversion into estrogen so lab work is certainly a necessity for an accurate picture. 

• Testosterone upgrades memory and helps protect against Alzheimer’s disease. According to Hertoghe, testosterone levels are much lower in men with dementia and that up to eight times less Alzheimer’s has been found in men with high testosterone versus men with low testosterone.

• While testosterone is considered a downstream hormone in addition to being very beneficial alone it also enhances the production of other crucial hormones such as Vasopressin, MSH (Melanocyte stimulating hormones),  Growth hormone, IGF-1, T3, Cortisol, DHEA, Aldosterone, DHT, and Estradiol.