Books on Buddhist Meditation -when we need books as Gurus

Buddhist meditation (in the core teachings of EBT) has two kinds: samadha (i.e. the practice of sati ‘mindfulness’) and insight (or ‘vipassana’, i.e. the practice of ‘right view’):

Why didn’t the Buddha provide a meditation manual? - The Watercooler - Discuss & Discover (suttacentral.net).

I think books as gurus for Buddhist meditation are the mentioned SN/SA suttas themselves.