Over all, it has good information, though some of it is incomplete and therefore misleading. Such as:
Bergamot elevates the mood and is good for alleviating anxiety and depression. The fragrance has a refreshing citrus aroma. Reported to increase white blood cell count. White blood cells fight foreign invaders in the body. Also reported to relax brain waves when inhaled.
Being in the citrus family, Bergamot can be phototoxic. Meaning that exposure to sunlight results in irritation after application. This oil is best saved for evening baths or application of lotions/oils, or in winter.
Chamomile relaxes both the mind and the body with a sense of inner peace and is good for headaches and insomnia. The fragrance might remind you of apples, as it did the Greeks who called the chamomile flowers earth apples. Chamomile leaves are said to bring peaceful dreams during sleep.
Chamomile is also very expensive, $25 and up for a 5 mL bottle.
Rose Geranium brings the mind and emotions back into balance. It is said to be able to stabilize blood pressure, although I don't know if this is based on any scientific studies. The fragrance is a combination of citrus and rose.
Actually, there have been scientific studies done on the effects of essential oils on blood pressure. Here is one published by the Touch Research Institute. Rose Geranium was not one of the oils in this study, and none of my reference books say anything about it's effects on blood pressure. It's fabulous for balancing the adrenals and reducing anxiety states through a sedative effect, though.
Jasmine sedates the nervous system while stimulating the brain and can relax tense muscles caused by tension, relieve headaches, and elevate the mood. According to one study, computer operators made fewer mistakes because of the scent of jasmine. Stress will lead to more mistakes, as will the mental distraction of stress.
Pure essential oil of Jasmine is almost impossible to find, and if you do, it's extremely expensive ($24 for 1 mL) due to the demand by the perfume industry. Absolutes are a step down from essential oils in refinement and more affordable.
Lavender is possibly the most common and widely-known as a stress reducer able to bring relaxation to the user and it is attributed in a long list of ability to promote calm. The fragrance is sweet and floral. Lavender is known to relieve muscle pain, ease headaches, fight inflammation, and supports the immune system. Research has proven lavender is the number one essential oil in relaxing brain waves and reducing stress.
Lavender is also known to amplify the effects of other essential oils so that the sum of a blend is greater than its parts. High altitude Lavenders from France or Italy are generally considered higher medicinal quality. Lavender is also one of the essential oils that has the widest variety of scents based on where it was grown, so if you don't much care for the smell, sniff around, you might be surprised. I personally dislike the smell of all Lavenders, except for the Italian High Altitude Lavender.
Sandalwood relaxes brain waves and is very calming for the nerves, lessening irritability, anxiety and tension. It is also an oil reported to increase white blood cell count. White blood cells fight foreign invaders in the body.
Sandalwood is incredible for nervous tension and stress related complaints. It has documented bactericidal and antiseptic properties. It is very small step in logic to say that when something is antiseptic, for example when you inhale Sandalwood, it increases white blood cells. I can understand the author not wanting to go out on a limb. After all, Sandalwood is famous for its effects on the respiratory system specifically.
If you are interested in more information, I recommend the The Encyclopedia of Essential Oils by Julia Lawless and the Pacific Institute of Aromatherapy. I prefer to buy my oils from their associated company, Original Swiss Aromatics.