Here’s an excerpt from Steenbakkers’s essay:
"Publishing the Ethics was a precarious undertaking. Spinoza himself put the manuscript away in 1675, and when his friends did publish it in the Opera Posthuma, they took safety measures to cover their activities. The book appeared without the publisher’s name (Rieuwertsz), without mentioning the place of publication (Amsterdam), and with the philosopher’s name abbreviated to ‘B.d.S.’ In the correspondence, references to people who were still alive were generally avoided and many factual allusions were discreetly suppressed. This covertness makes it difficult to determine who the editors were and what they did with the manuscripts they had at their disposal."