Short answers, pulled from the story.
The Śālistamba Sūtra takes its name from Sanskrit words meaning "rice stalk" or "rice sapling." The image of a plant growing from specific conditions reflects the sutra's central concern with how all phenomena arise from causes.
N. Ross Reat argues the Śālistamba Sūtra could date as far back as 200 BCE. That estimate would place it at a moment before the Mahāyāna had emerged as a fully distinct movement within Buddhism.
N. Ross Reat produced the first complete English translation of the Śālistamba Sūtra. His 1993 edition, published in Delhi by Motilal Banarsidass, includes the Tibetan original, a Sanskrit reconstruction, and critical notes comparing the Pāli parallels, the Chinese versions, and ancient Tibetan fragments.
Roughly 90 percent of the Śālistamba Sūtra survives through quotations in other Buddhist Sanskrit works; the sutra was the most widely quoted Mahāyāna text on dependent origination. Louis de La Vallée-Poussin began reconstructing the Sanskrit from those citations in 1913. The sutra also exists in six Chinese translations and in various Tibetan recensions, including manuscripts found at Dunhuang.
The Śālistamba Sūtra elaborates on pratītyasamutpāda, the Buddhist doctrine that all phenomena arise from specific conditions. Using a simile of a seed producing a plant, it illustrates how experience requires a particular gathering of causes. The sutra states that seeing conditioned arising is the same as seeing the Dharma and seeing the Buddha.
Three commentaries attributed to Nāgārjuna survive in Tibetan, recorded in the Peking catalog as numbers 5466, 5485, and 5486. Kamalaśīla, the eighth-century Indian scholar, wrote a fourth commentary called the Śālistambakaṭīkā. Jeffrey D. Schoening later published an academic study of the sutra alongside its Indian commentaries.
The Śālistamba Sūtra is counted among the first Mahāyāna sūtras because it is attributed to the bodhisattva Maitreya rather than the historical Buddha, focuses on the Dharmakāya, and uses the term māyā to gesture toward a view of reality as illusory. The text promises that fully understanding dependent arising leads to becoming a perfectly enlightened Buddha, a distinctly Mahāyāna aspiration. N. Ross Reat notes that its proto-Mahāyāna transmitters were not trying to break from earlier tradition but to systematize it.