The Basics

• Buddho, by Ajaan Thate
  A simple and practical guide to the use of the meditation phrase, buddho, which is used to settle the mind to the point at which discernment can begin to arise.
• A Guided Meditation, by Thanissaro Bhikkhu
  Basic instructions in the practice of breath meditation.
• Keeping the Breath in Mind and Lessons in Samadhi, by Ajaan Lee Dhammadharo
  A complete handbook for breath meditators, full of detailed practical instructions for the development of concentration and insight.

Further Reading

• Steps Along the Path, by Ajaan Thate
  A short handbook on the practice of meditation, with tips and recommendations for new and experienced meditators. Of particular interest is Ajaan Thate's discussion of how best to respond when visions and signs arise during the course of meditation practice.
• Ajaan Sao and his student Ajaan Mun established the Kammatthana tradition. A true forest-dweller, Ajaan Sao left no written records of his teachings. Fortunately for us, another of his students -- Phra Ajaan Phut Thaniyo -- recorded Ajaan Sao's Teaching: A Reminiscence of Phra Ajaan Sao Kantasilo, which offers us a glimpse of Ajaan Sao's terse but powerful teaching style.
• Jhana Not by the Numbers, by Thanissaro Bhikkhu
  The author recalls how Ajaan Fuang taught meditation to his students: he would give them just enough instruction to stay on-track, but would rarely "certify" them as having attained this or that level of jhana, thereby motivating them to develop self-reliance and ingenuity in their meditation. In the words of Ajaan Fuang: "If I have to explain everything, you'll get used to having things handed to you on a platter. And then what will you do when problems come up in your meditation and you don't have any experience in figuring things out on your own?"
• Stop, Look, and Let Go, by Upasika Kee Nanayon, translated from the Thai by Thanissaro Bhikkhu
  A talk covering a variety of topics, all concerning the need for being observant in watching over the mind. Memorable quote: "People who are intelligent and discerning prefer criticism to praise. Stupid people prefer praise to criticism."